Note: Descriptions are shown in the official language in which they were submitted.
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GASEOUS WAVE REFRIGERATION DEVICE WITH
FLOW REGULATOR
Background of the Invention
This invention provides a gaseous wave refrigeration device (GWRD) with a
flow regulator, a wave impedor, and chiller to monitor the gaseous wave
behavior in
GWRD and to produce the refrigeration effectively. This characteristic is
achieved by
means of controlling resonant periodic flow phenomenon of gaseous column and
wave
interactions under varying conditions of flow states in pressurized supplying
gas streams
1o through GWRD.
As is known widely in the industrial fields, gaseous expansion refrigeration
processes are applied in a variety of operations, such as condensation, gas
separation, gas
liquefaction, and oil refining of traditional chemical and petroleum
industries.
Meanwhile, the rapid development of small meclianical cryocoolers in the high-
tech
fields which use the gas expansion cycles over the past decades is due to the
emergence
of specific applications in low-temperature operation with the requirement of
a long life
running. All of them are operated under pressurized gases expansion processes
or relative
gaseous expansion cycles. The primary feature of gas expansion cooling devices
afore-mentioned is that the temperature drop or cooling load is obtained by
the cycle
extracting the energy or work from the expanded gases by mechanic parts --
either the
type of pistons, displacer, or impellers.
Generally speaking, gaseous cooling devices may vary according to different
mechanic structure, device size, operating conditions, and thermodynamics
cycles.
However, they can all be classified by the cooling capacity and the range of
applications
of such a device in the systems. For instance, many gaseous expansion
equipments such
as turbines and piston expanders are designed for high cooling capacity mainly
in
petrochemical industries, whereas small cryocoolers such as G-M coolers,
Stirling
coolers, pulse-tube coolers, and adsorption cooler for the applications in
infrared
detectors for earth observation, night vision, and missile guidance are mainly
designed to
work under different working environments with small cooling capacity.
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However, Almost all the current cooling devices designed have one common
feature in terms of their cooling mechanism: they all have mechanically moving
parts to
absorb pressure energy from cold gases and to achieve the cooling effects. The
utilization
of mechanical structures in the gaseous expansion device improves the
operation
efficiency in thermodynamic cycles and increases the cooling effect. On the
other hand,
it causes the drawbacks of low running reliability, high cost of maintenance,
limitation of
operation conditions. Therefore, in past several decades new efforts had been
made to
develop the new type of gaseous expansion devices in order to overcome the
fatal
disadvantage in the traditional devices
Due to the development of new technology and the stimulation in the relative
high-technical industries such as magnetic resonance imagery systems,
superconductivity
applications, and high energy facility, there has been an increasing interest
in developing
new devices for extreme special conditions with very high pressure drop, very
lower
temperature environment, long-life running, and fluctuating operating
condition, etc.
where the traditional cooling devices for gaseous expansions fail or lack
inefficiency. In
order to replace inefficient traditional equipment and retain merits of simple
structure,
low initial investment, and low maintenance cost, considerable improvements
have been
made in this field for the consideration of effective operation as employed in
the previous
arts by U.S. patents #2765045, #2825204, #3200607, #3314244, #3,541,801,
#3526099,
#3559373, #3,653,225, #3,828,574, #3889484, #3904514, #4383423, #4444019,
#4504285, #4531371, #4,625,517, #4,722,001.
All the inventions have limited success in overcoming the problems mentioned,
because they all contain some moving parts which will usually lead to low
liability and
high maintenance cost though some of them are operated on the improved
mechanism or
structure. Generally, in order to avoid the mechanically moving parts as
required by
system reliability, Joule-Thomson valves (throttling valves) have to be used
as the
element.to obtain cooling capacity. The mechanism of the J-T valves is based
on an
isoenthalpic process during the pressure drop of gas expansion. Although it is
still the
most popular alternative for industrial gaseous expansion and pressure
regulation
processes owe to its simplicity, reliability, low cost maintenance, and easy
controllability, nevertheless, J-T valves have a very low cooling efficiency
which results
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in high loss of pressure energy in the gas cooling processes. Obviously, its
wide
application is due to the fact that to obtain cooling effect by pressure
reduction in the
certain technical processes, using throttling valves instead of traditional
energy extracting
machines is the only possible solution to the extreme working conditions such
as high
pressure and two-phase flow.
Therefore, a device which will increase the cooling efficiency without any
mechanical moving parts and at the same time retain the merit of J-T valves
always
challenges the manufacture of gas expansion equipment and attract the
industrial users.
In the previous arts, the idea to create cooling effect by means of gaseous
wave
1o interaction in periodic unsteady flows has already been proved and reported
by U.S.
patents #3,541,801, #3,653,225, #3,828,574, #4,625,517, #4,722,001, especially
#5412950. However, none of the previous arts with these and other mechanism
have ever
proposed a device running effectively with the merits of no moving parts,
simplicity,
reliability, easy regulation, and low cost for maintenance under the varying
flow
conditions which frequently occurs in industrial practices. Therefore, the
prior patents
with these and other mechanism have limitations in terms of their efficiency,
simplicity,
controllability, and reliability in the scope of industrial applications.
Although there are
several devices which used a pulsating flow to generate cooling effect in
prior art patents,
there still exists no device with enough cooling capacity, free of complex
structure and
moving parts, and suitable for the controllability for flow state fluctuation
like valves in
industrial practice. In addition, it is also very difficult to find the
existing gaseous cooling
devices which can work effectively (or to be more specific limitation in
cooling capacity,
or won't have the required stable operation) under the condition of varying
flow state in
industrial systems within the high pressure drop range as well. These and
other
difficulties experienced with prior arts of gaseous cooling devices and the
needs of
engineering applications in the variation of operating flow conditions have
been
motivated in a novel manner of the present invention.
In comparison with traditional refrigeration equipment and the existing types
of
gaseous wave refrigeration devices in the previous arts, the present
invention, for its
primary object, introduces an apparatus, which works by using the mechanism of
resonant gaseous wave for cooling processes under the varying condition of
flow state.
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The present invention overcomes the limitations and weak points with the
previous arts
in terms of gaseous wave refrigeration device in U.S. patent #5412950.
The Applicant's apparatus in the present invention is designed for the GWRD
operation under the varying condition of flow state in supplying pressurized
gas stream,
which is often met in all industrial systems and makes the GWRD operation
inefficiency
or failure. The apparatus's operation is established on the special mechanism
to control
gaseous wave resonance flow production for the best performance of GWRD by the
mechanical regulating structure which can minimize the effect of flow state
variation on
the periodic gaseous wave system behavior. In addition, the apparatus in the
present
1o invention can also be adjusted to responses the variation of active flow
state as required
by monitoring processes in most industrial systems. The apparatus in the
present
invention is especially suitable for technical processes in industries where
the flow state
of supplying pressurized gas stream is needed to be monitored actively and
adjustable
manually to obtain the effective cooling operation, or the case in which the
respondence
has to be taken for the passive fluctuation of flow states in supplying
pressurized gas
stream due to undesirable reasons.
Most importantly, the present invention also improves over the previous art
U.S.
patent # 5412950 which failed to produce cooling effect efficiently at varying
flow state
due to the change of gaseous wave interactions in the oscillating chamber. By
contrast,
the gaseous wave refrigeration apparatus in the present invention provides an
effective
instrument for systems and processes in petrochemical and natural gas
industries where
(a) conventional throttling valves have been used to generate the cooling
effect, (b) the
flow state passing the throttling valve is needed to be actively monitored and
adjustable
for the required variation of cooling load and optimized operation, and (c)
the flow state
changed passively due to the need of processes operation in which the maximum
cooling
effect is hardly obtained for the required load from existing throttling
valves.
In short, the present invention aims at meeting several important objectives.
The
first is to provide a gaseous wave refrigeration apparatus for applications
where
traditional expansion machines can not be used or are used with low efficiency
at varying
flow states.
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The second is to provide a gases wave refrigeration apparatus for replacement
of
throttling valves with a flow state regulator manually to monitor actively the
recovery of
the high pressure drop energy from the gaseous expansion processes in
industrial
systems.
The third is to provide a gaseous wave refrigeration apparatus to handle the
flow
state variation passively in industrial system and generate the maximum
cooling
performance by adjusting the wave interaction behavior in said gaseous wave
refrigeration apparatus.
The last is to provide a gases wave refrigeration apparatus which can operate
1 o under the extreme high pressure drop by means of a multi-stage operation
in series.
Meanwhile, the flow state in each stage can also be controlled by means of a
flow
regulator in GWRD for maximum pressure energy recovery and cooling effect
without
using any moving parts.
With these and other objectives in view, as will be apparent to those skilled
in the
art, the invention resides in the combination of parts set forth in the
specification and
covered by the claims appended hereto.
Summary of the Invention
The apparatus (GWRD) in the present invention employed a means to monitor the
gaseous wave behavior inside GWR.D and produce the refrigeration effectively
under
conditions of flow state variations in pressurized supplying gas streams
through GWRD.
It is accomplished by controlling resonant periodic flow phenomenon of gaseous
column
and wave interactions using an adjustable nozzle within a mobile space of
oscillating
chamber, a wave impedor, and a chiller. The apparatus primarily comprises, a
flow buffer
chamber, a jet nozzle which is adjustable to response the varying flow state
by changing
its cross-section at the exit, a mobile oscillating chamber which contains a
regulating unit
to retain a steady high speed jet oscillation and respond to the nozzle
adjustment
synchronously, a flow stabilizer which reduces the interacting mixture in the
outflow of
the resonant tube bundles, a bundle of resonant tubes which produces and
dominates a
pulsating flow in the mobile oscillating chamber and converts the gas stream
kinetic
energy into cooling and heating effect by means of the interaction of resonant
waves,
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thermal isolators which are linked between the mobile oscillating chamber and
each of
resonant tubes to isolate the heat conducted from resonant tubes into the
mobile
oscillating chamber, a wave impedor which can modulate the periodic shock wave
system to reduce the reheating effect of reflected compressive wave on cold
gases in the
aperture of resonant tubes, and a chiller which is used to enhance the heat
transfer from
the surface of resonant tubes.
Generally stated, the apparatus in the present invention is designed to retain
the
best performance of GWRD operation under the conditions of varying flow
states.
Variations of flow states are the common cases in which GWRD is enforcedly
operated
in the off-designed-working condition due to the expectable or undesirable
reasons in
practices. From experimental observations of the previous art U.S. patent #
5412950, the
changes of flow state through GWRD influences seriously the spontaneously
self-sustained oscillation of high speed jet occurred in the oscillating
chamber, which
makes the off-designed operation of GWRD very ineffective.
As a matter of GWRD operation, pressurized supplying gas streams converts its
pressure energy into the kinetic energy and forins a high-speed jet through
the nozzle.
When entering the oscillating chamber with a special confined space, the high
speed jet
structure maintained by pressurized gas stream in the steady flow state, will
be
dominated by its inherent characteristics, such as the length of shear layer
separation
2o region, the non-uniform flow entrainment, and the turbulent diffusion at
downstream.
Those parameters critically determines the jet deflect behavior apart from the
flowing
direction of the nozzle exit axis. As the deflected high-speed jet impacts
with each of the
resonant tubes which are placed into the instability region of high-speed jet
structure, a
feedback phenomenon of the pressure waves is produced along the high-speed
jet. As a
result, this pressure feedback pushes the high-speed jet moving normal to its
flowing
direction in the oscillation chamber and sweeping over the inlets of resona.nt
tubes to
make the pressure feedback in succession. With the GWRD operates at a steady
status,
the feedback process is entirely depended on several critical parameters, such
as resonant
tube forms, interference spacing between the nozzle exit and resonant tube
inlet, a
structure of the stabilizer, geometrical shape of oscillating chamber, and
length of the
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each resonant tube. Those parameters dominate to sustain a steady periodic jet
flapping
process in the oscillating chamber and a resonant cooling effect in GWRD.
Normally, the steady flow state at the designed-point is the nominal operating
conditions required by system operations, by which the GWRD is designed to
achieve
the expected cooling capacity. In industrial systems, occasionally, the flow
state in the
pressurized supplying gas stream varies due to the fluctuation of system
productivity and
undesirable factors in supplying gas sources. Such a change in the flow state
of supplying
gas sources will result in the GWRD to be operated in off-design conditions
and degrade
the performance efficiency because the structure of the high-speed jet will
1o consequentially follow the flow state varying. In this case, the
reorganization of the jet
structure in varying flow state normally weakens or disorders the periodic
feedbaclc
processes between the jet and resonant tube bundles which sustains the
periodic
oscillation of high speed jet in the chainber. Once disordered jet oscillation
happens, the
GWRD operation fails due to that the energy conversion inside resonant tubes
is
degraded or disappeared.
As to maintain effective operations, the apparatus in the present invention
involves an adjustable nozzle and a mobile oscillating chamber to generate a
stable
operation of GVWRD under the condition of varying flow states. The adjustable
nozzle
and the oscillating chamber are simply designed to be moved simultaneously in
the
2o direction perpendicular to jet flow. By this mechanism, it will retain the
high-speed jet
structure at the designed condition and diminish the effect of varying flow
states on the
oscillating chamber in the certain range. Meanwhile, the steady performance of
GWRD
will be established upon the adjustment of the mobile nozzle and the
oscillating chamber
simultaneously, which make the jet oscillation and wave system interaction
behavior in
order. In addition, the uses of a wave impedor and a chiller will reduce the
sensitivity of
the high-speed jet structure and sustained-oscillation to the flow state
variation.
Brief Description of the Drawings
The characteristics of GWRD in the present invention, may be best understood
by
3o reference to one of its structural forms illustrated by the accompanying
drawings in
which:
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Figure 1 is an exploded side view of the GVJRD apparatus
Figure 2 is a bottom view with partially exploded view of GVWRD apparatus,
Figure 3 is a top view of GWRD apparatus in the present invention,
Figure 4 is a perspective schematic view of the GWRD apparatus
Detailed Description of the Preferred Embodiment
By the side exploded view, FIG. I best describes the general features of
mechanical
structure of the GWRD in the present invention. The said GVJRD apparatus
comprises a
upper cover plate 1, a inlet conduit 2, a flow buffering chamber 3, a lower
cover plate 4,
a nozzle 5 which has the convergent or convergent-divergent passage and is
coimected
with the flow buffering chamber 3, a vortex stabilizer 6, a discharging
conduit 7, an
oscillating chamber 8 which is arranged in series of the convergent nozzle 5
and
connected to one end of each of the resonant tubes, a flow regulator 9, a
middle operating
plate 10, thermal isolated cormectors 11 which connect between the middle
operating
plate 10 and the open end of each resonant tube 14, wave impedors 12 which are
connected to the other end of each resonant tube, a chiller 13 which is
penetrated by all
resonant tubes, a bundle of resonant tubes 14, a regulating spindle 15 which
is linked to
flow regulator 9, a screw cage 16 which holds and moves the spindle 15 up or
down
when the spindle 15 is rotated, a regulator holder 17, a packing gland 18, a
bushing 19, a
handwhee120, fasten bolts 21.
Again referring to FIG. 2 and 3, the upper cover plate 1 and lower cover plate
4
hold the middle operating plate 10 from both sides by several fasten bolts 21
to form the
main body of GWRD. The said middle operating plate 4 contains the buffer
chamber 3,
the nozzle 5, and the mobile oscillating chamber 8. The said middle operating
plate 4 is
directly connected to one end of the bundle of resonant tubes 10 in the way
from the side
wall through the thermal isolated connector 11, by which to fonn a fan shape
distribution
in the external extent of resonant tubes. The inlet conduit 2 is mounted on
the opposite
sidewall of the middle operating plate 4 to lead the pressurized gas stream
straight into
the buffer chamber 3. The flow regulator 9 is assembled within the oscillating
chamber 8
from the perpendicular direction to change the flow passage spacing in the
oscillating
cliamber 8 by gradually moving into the inside of the chamber 8. The upper
surface of
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flow regulator 9 is linked to spindle 15 which enables this to move the flow
regulator 9
up and down by the rotation of the spindle 15. The spindle 15 is penetrated
through the
screw cage 16, the packing gland 18, and bushing 19. The end of spindle 15 is
finally
fenluninated to the handwheel 20. The discharging conduit 7 is attached to the
hole on
the lower cover plate 4 to form the discharging passage. The discharging
passage formed
is connected to the vortex stabilizer 6 which is on the middle plate 10. The
opening end
of each resonant tube 14 is jointed to the middle operating plate 10 through
each of the
thermal isolated connectors 11, and the other end of each resonant tube 14 is
inserted into
one of wave impedors 12 which has the container shape to form the enlarged
cross-section at the end of resonant tubes 14. The bundle of resonant tubes
penetrate the
sidewall of the chiller 13 in following their radial direction. On the
sidewall of shell
space of the chiller 13, there are inlet and outlet passages leading the
coolant tlirough the
chiller carrying the heat away from the surface of the resonant tube bundle 14
inside the
chiller 13. The bushing 19 is screwed on the holder of spindle 17 to extrude
the packing
gland 18. The extruded packing gland 18 seals around the cylindrical surface
section of
the spindle 15 to separate the internal gas stream inside the oscillating
chamber 8 from
the surroundings.
Further primarily referring to FIG. 1, when a pressurized gas stream with a
steady
flow state from discharging source flows into GWRD apparatus in the present
invention,
it first is led into the buffer chamber 3 by the inlet conduit 2. The
turbulence and vorticity
generated from the inlet passage are reduced and the stagnation pressure of
the coming
pressurized gas stream is recovered in the flow buffer chamber 3. Since the
inlet conduit
2 is aligned to the outflow direction of the nozzle 5, the impinging loss and
vorticity
generation stemmed from the change of flow direction inside of the buffer
chamber 3 are
diminished, and the stagnation pressure of the coming pressurized gas stream
is
effectively retained. As the pressurized gas stream rushes out of the nozzle
5, the
pressure energy of the pressurized gas stream is converted into kinetic
energy, and a high
speed jet structure is formed in the oscillating chamber 8. In principle, as
the high-speed
jet is injected into the oscillating chamber 8 with the geometrical
enlargement of flow
section from the nozzle 5, the flow separation is formed accompanied with the
formation
of high shear layer. The further development of the high speed jet entirely
depends on the
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boundary conditions at the down stream in the oscillating chamber 8, which
are, in the
present case, the side wall configuration, spacing between the exit of the
nozzle 5 and the
aperture of resonant tubes, and the length of the resonant tubes. The
configuration of the
confined space in the oscillating chamber 8 will seriously influence the
stability of
high-speed jet.
However, as to excite the instability of high-speed jet and form the periodic
self-sustained oscillation inside the oscillating chamber 8, those geometrical
parameters
have been carefully selected under the given operating condition of GWRD. For
the
purpose of producing a periodically unstable jet flow in the oscillating
chamber 8, the
offset of the side walls in the oscillating chamber 8 plays a key role to make
the jet
deflection to one side of both walls in the oscillating chamber 8. With the
formation of
the high-speed jet bending, the status of critical neutral stability is
established in the
oscillating chamber 8, under which it is easily triggered into an unstable jet
by small
pressure disturbances from downstream. If there is no downstream boundary, for
instance, without the existence of resonant tubes, the high-speed jet will
steadily stay in
the bending state at the initial side of the walls. As a matter of fact, the
existence of the
bundles of resonant tubes 14 at downstream of the oscillating chamber 8
functions to
generate the pressure wave disturbances, and triggers the instability of the
bending jet.
In addition, once the bending jet in GWRD reattaches at the initial side wall
of
the oscillating chamber, it impacts with one of the bundle of resonant tubes
14 at
downstream, a strong pressure wave disturbance is produced immediately at the
aperture
region of those tubes due to the instantaneous accumulation of fluid mass.
This strong
pressure disturbance propagates along the both directions, up and down stream
around
the impinging point. The one traveling to upstream, called feedback pressure
wave
disturbance (FPWD), has a strong effect on the bending behavior of the high
speed jet,
and the other moving to downstream, called incident pressure wave disturbance
(IPWD),
induces the resonant oscillation of the gaseous column remaining (GCR) inside
the
bundle of resonant tubes 14. Under the action of the generated FPWD, the state
of the
shear layer of high-speed jet at the sensitive region out of the nozzle 5 has
been changed
3o and becomes unstable. The adjustment of the bending behavior of high-speed
jet in the
oscillating chamber 8 results from the FPWD arrivals at the nozzle 5 exit. The
state
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variations of the shear layer in the outlet region of nozzle 5 gradually
changes the initial
direction of jet flow which generates the movement of the bending jet step by
step in the
oscillating chamber 8 as it sweeps over each aperture of the resonant tubes
14. The
identical interaction processes between the jet and the resonant tubes will
begin when the
moving high-speed jet reaches the other sidewall of the oscillating chamber 8.
Based on
the mechanism of FPWD interacting with the high-speed jet, a lateral self-
sustained
oscillation of high-speed jet is generated to form the fimdamental operation
of the
apparatus in the present invention. When the self-sustained oscillation is
triggered, the
high-speed jet flaps periodically over all the apertures of the bundle of
resonant tubes 14.
Associated with the excited jet oscillation aforementioned, the cooling effect
is
obtained in the vicinity of the aperture of the bundle of resonant tubes 14.
It is because
the periodic generation of IPWD at the apertures of resonant tubes induce GCR
oscillations during the jet interacting with GCR, and removes the energy from
the gas
portion injected by the flapping jet. As IPWD propagates from the aperture
toward the
closed end of resonant tubes 14, the internal energy of injected gas is
reduced. In fact,
when the high-speed jet moves away from the impinging aperture of resonant
tube, the
injected gas rushes out from the resonant tube 14 into vortex stabilizer 6
with a
significant temperature drop. At the moment, an incident expansion wave
disturbance
(IEWD) is formed and travels into the resonant tube as well.
Noticed that an interface between the injected gas and GCR is formed in the
vicinity of the aperture of resonant tubes 14 to separate them into different
energy
regions, namely the portions of injected gas and remaining gas. The portion of
injected
gas is refreshed as the jet flaps over the apertures of resonant tubes, and
the remaining
gas resides in resonant tubes to absorb the energy released by the injected
gas in the form
of IPWD. Due to the contribution of nonlinear effect, the front of IPWD
becomes steep
during the movement. Finally, an incident shock wave disturbance (IS)VD) is
formed
before IPWD reaches the other end of the resonant tubes 14. The majority of
energy
portion released by the injected gas is dissipated by (ISWD) in the remaining
gas and
raises the temperature of GCR significantly.
Generally speaking, the operation of GVWRD in the designed flow state is based
on IPWD system's performance which acts as a vehicle to transport the pressure
energy
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from the injected gas into surroundings. This process of the energy
transportation relies
upon the generation of resonant oscillation coupling the high speed jet
structure with the
geometry of the oscillating chamber 8 and resonant tubes 14 selected for the
designed
flow state. Unfortunately, there are several factors effected seriously on the
jet structure,
including the shear layer thickness, potential core region length, shock disk
position, and
entrainment ratio, etc., which all are sensitive to the flow state. Due to the
fact of the
geometry critically creating the gaseous wave interaction spontaneously, the
variation of
flow state will sensitively change the GWRD operation.
Supposing that the flow state turns away the designed-point, the initial
response
1o to GWRD operation is to bring the variation of flow state at the exit of
the nozzle 8. At
first, the velocity at the exit of nozzle 8 will be changed wliich directly
takes the action to
the high-speed jet structure. As a consequence, the state of lateral self-
sustained
oscillation of high speed jet will be disturbed, weakened or will become
irregular since
the matching conditions to sustain the jet oscillation at the designed flow
state is broken
down. Apparently, the discordance of the oscillating condition directly
results in the
degradation of the refrigeration performance of GWRD. Observed from the
experiments,
the cooling performance of GWRD in the prior art of U.S. patent #5412950 drops
down
because the flow rate or supplying pressure diverges from the designed
conditions.
Therefore, it is realized that the adjustment of all geometrical parameters in
the
oscillating chamber 8 is imperative to rematch resonant oscillation conditions
under the
variation of flow state. The difficulty of making this adjustment is because
the limitation
of device size and internal leakage will result in the complexity of
mechanical structure
to adjust all parameters simultaneously inside the oscillating chamber 8 to
match the
unknown wave system conditions.
In order to recover the refrigeration performance of GWRD at the varying flow
state, the apparatus of the present invention provides the method and
mechanism to
regulate manually the oscillating chamber 8 and nozzle 5 simultaneously to
maintain the
optimal cooling operation of GVWRD with the simplest structure. Further
referring to FIG
1 again, it discloses the features of the apparatus in the present invention.
The flow
structure of a high-speed jet created in the present apparatus has the two-
dimensional
flow feature partially inside the oscillation chamber 8 and is uniquely
determined by the
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exit velocity of -nozzle 5. The method proposed in the present invention is to
regulate the
critical geometry of GWRD under the conditions of varying flow state by
changing the
spacing of the jet flow passage in the direction perpendicular to the two-
dimensional
flow space of the oscillating chamber 8. By doing this way, the jet flow
structure and
designed geometry will be minimally affected by the geometrical adjustment
during the
varying flow state. In principle, it is based on the fact that the geometrical
adjustment of
flow passage in the direction perpendicular to flow confined space of the
oscillating
chamber 8 will provide the identical flow pattern and structure of high speed
jet with the
designed point in the oscillating chamber 8 when the flow state varies. The
adjusting
procedure is accomplished by the following steps: once the flow state turns
away from
the designed-point, for instance in the case of the flow rate dropping down,
the jet speed
at the exit of the nozzle 5 will reduce immediately. The reduction of the jet
exit velocity
of nozzle 5 weakens the interaction of the jet with the resonant tubes 14 due
to the
degeneration of the jet strength. To respond to this flow rate drop, the flow
regulator 9
which is inserted into the oscillating chamber 8, will be pushed down by
rotating the
spindle 15 manually. The left-side wall of the flow regulator 9 coiitacted to
the exit wall
of the nozzle 5, will gradually block the exiting section of the nozzle 5 from
the
perpendicular direction as the flow regulator 9 slides down into the
oscillating chamber
8. The reduction of the flow exiting area of the nozzle 5 results in
increasing the rushing
velocity of high speed jet back to the designed-point value. Meanwhile, the
flow passage
in the oscillating chamber 8 is shrunk as the flow regulator 9 moves down
which matches
with the geometrical change at the exiting section of the nozzle 5. Since the
simultaneous
adjustment of the oscillating chamber 8 and the nozzle 5 retains the pattern
of the jet
flow structure at the designed point at the moment of the flow rate dropping,
the
self-sustained oscillation of high speed jet is retained and the cooling
performance of
GVWRD under the varying flow state is maintained. For the reverse operation of
the flow
regulator 9, it will be suitable for the flow rate increasing case. Since the
geometrical
configuration of the oscillating chamber 8 in the middle operating plate 10 is
lcept with
the adjustment of the spacing in the direction perpendicular to the jet flow,
except for the
3o boundary effect developed on the upper and lower walls of the oscillating
chamber 8, the
performance of GVdRD is recovered in the certain range of flow state
variation. This
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mechanism regulating flow pattern in the varying flow state insensitizes GWRD
apparatus to the operating condition, and makes the apparatus in the present
invention
practicable for the industrial operations. Structurally, to seal the leakage
of the
pressurized gas stream inside the oscillating chamber 8 from the wall of the
spindle 15
into the surroundings, the sealing unit including the regulator holder body
17, the
packing gland 18, and the bushing 19 are designed. The regulator holder body
17 holds
the packing gland 18 which has the annulus shape to be penetrated by the
spindle 15. The
packing gland 18 is tightly pressed by the bushing 19 to seal the contacted
cylindrical
surface of the spindle 15.
In addition, from the experimental observations, it is found that the heat
generated from GVdRD operation is accumulated in GCR. It results in the
increment of
the average temperature of GCR if the heat is not removed effectively. The
heat
accumulation and the temperature increase in GCR changes the state of the
interface,
degrades the energy transportation between the injected gases and GCR, and
weakens the
behaviors of IPWD and ISWD propagating in GCR. On the principle of gas
dynamics,
the higher the temperature of GCR, the lower the cooling efficiency generated
in the
injected gases. However, In order to increase the cooling effect and intensify
the IPWD
and ISWD behaviors for pressure energy transportation, in the apparatus of the
present
invention, the chiller 13 is designed to enhance the heat released from GCR.
The heat
generated by the resonant oscillation of GCR is carried away by the convective
heat
transfer between the surfaces of the bundle of resonant tubes 14 and the
coolant which
flows through the shell of the chiller 13. Meanwhile, the heat conducted from
the
resonant tubes 14 into the oscillating chamber 8 which reheats the injected
gas is
eliminated by the installation of the thermal isolated connector 11.
Referring to FIG 2 and 3 again, it is found that from experiments, as ISWD
reaches the other end of resonant tubes 14, a reflected shock wave disturbance
(RSVWD)
is generally formed which travels back along the opposite direction of ISWD if
the
closed-end wall of the resonant tubes is imposed. Since RSWD carries the
significant
pressure energy, when passing through the interface from the opposite side, it
reheats the
portion of the injected gas. This reheating process normally degrades the
efficiency of
pressure energy transportation from the injected gas into GCR in the resonant
tubes 14,
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and reduces the refrigeration performance of GVJRD in the design conditions as
well. On
the other hand, the RSWD will interfere with the FPWD system if it is not
controlled
properly. In the varying flow state, the RSWD will intensify the disordered
oscillation of
jet. In order to diminish the reheating effect on the injected gas, the
configuration of the
closed end of resonant tubes 14 is replaced by the wave impedor 12. The wave
impedor
12 is a short cylinder with a larger diameter which forms an enlarged cross-
section linked
at the end of resonant tubes 14. Once applied the wave impedor 12, the
intensity of
RSWD is artificially diminished and the reheating of the injected gas is
eliminated. The
length and diameter of the wave impedor 12 depends on ISWD parameters imposed.
It is
also noticed that the installation of impedor 12 will benefit the GWRD
operation in the
varying flow state by the elimination of RSWD effect on the high-speed jet
oscillation in
the oscillating chamber 8.
In summary, because the propagation of the periodic FPWD in the shear layer of
the high speed jet drives the jet repeatedly sweeping over the each aperture
of resonant
tubes 14, the self-sustained oscillation of high speed jet couples in reverse
with the
resonant oscillation behavior of GCR to generate refrigeration effect on the
portion of the
injected gas. The generation of refrigeration is produced by the interactions
of wave
systems such as IPWD, RPWD inside the resonant tubes 14, and the injecting
processes
of high-speedjet into the resonant tubes 14. Both processes are critically
triggered by the
geometrical parameters of the nozzle 5 and the oscillating chamber 8, which
dominate
the interaction between the high speed jet and resonant tubes 14. When the
flow state of
supplying pressurized gas varies, it usually makes the GWRD operation degrade
from
off-designed point due to the change of the high-speed jet structure. Such a
change will
weaken or rain the aforementioned two interaction processes and result in the
failure of
GVWRD operation at the varying flow conditions. To retain the best performance
of
GWRD in the varying flow state, the apparatus in the present invention employs
the
mechanism to adjust the high-speed jet structure in the varying flow state to
minimize the
effects of additional adjustable mechanical structure on the internal leakage
and
mechanical complexity. Increasing the cooling efficiency of GWRD and reducing
interfere of RSWD on the oscillating jet in steady or varying flow condition,
the wave
impedors 12 and chiller 14 are designed in the apparatus of present invention.
The wave
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impedors 12 fimction to diminish the reheating effect on the injected gases
caused by
RSWD, and the chiller 14 is to reduce the temperature of the interface and to
intensify
the energy transportation between the injected gas and GCR. In addition, the
thermal
isolated connector 11 is used also to eliminate the heat conducted from the
wall of the
resonant tubes into the oscillation chamber 8.
With all the means, the apparatus in the present invention can be operated in
the
varying flow condition. The application of the flow regulator 9 makes the GWRD
apparatus be able to work in a wide range of flow conditions and retain the
performance
at the designed-point. It is indicated that the steady self-sustained
oscillation in the
apparatus will be maintained by the proper manual adjustment of the nozzle 5
and the
oscillating chamber 8. For the case with extreme high pressure drop, the
apparatus in the
present invention can be operated in series, and the maximum temperature drop
in the
varying flow state can be achieved by the separate adjustment of GWRD in the
each
stage.
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