Method and device for pressure jumps in two-phase mixtures

An improved device for acting upon fluids by means of a pressure jump is disclosed. The device consists of a nozzle which receives an active fluid. A passive fluid is provided to the nozzle such that it mixes with active fluid to form a two-phase mixture flowing with subsonic velocity. The passive fluid when mixed with the active fluid partially evaporates thereby increasing the stagnation pressure of the mixture and decreasing its stagnation temperature. An expansion chamber is joined with the nozzle where the two-phase mixture is accelerated. An outlet channel with constant cross-sectional area is connected to the expansion chamber. In the outlet channel, the mixture is accelerated to its supersonic velocity so as to create a pressure jump. The nozzle of the device comprises at least one working section and at least one control section. In the working section, the passive fluid is provided into the flow of the active fluid to create a two-phase mixture. In the control section, which is joined with the expansion chamber, additional mass is provided to the flow of the two-phase mixture so as to adjust the ratio of gas and liquid phases in the mixture for achieving a pressure jump of the desired intensity in the outlet channel.

FIELD OF THE INVENTION 
This invention relates to a pressure jumps in multi-phase fluids. Such 
fluids can be liquids gases and vapors and may include solid particles 
dispersed therein. In particular, this invention relates to pressure jumps 
in two-phase fluids. 
BACKGROUND OF THE INVENTION 
In the parent application, which is incorporated in its entirety herein by 
reference, there is described a method and device for accelerating a 
two-phase mixture of at least two fluids moving with subsonic velocity to 
sound velocity, then accelerating it to supersonic velocity such that the 
mixture is brought to a final pressure through a pressure jump (or shock 
wave) substantially as a one-phase mixture. 
One of the fluids in the two-phase mixture is referred to as an "active" 
fluid, and the other fluid is referred to as a "passive" fluid. Typically, 
but not always, the active fluid is gas that supplies energy for 
transporting the passive fluid, which is a liquid. 
The apparatus disclosed in the parent application takes advantage of the 
physical phenomenon of an enhanced compression in homogenous two-phase 
flows or mixtures. In such mixtures, the sound velocity is lower than in 
either only the liquids or gases (vapors). 
The compressibility of a flowing medium is represented by Mach number, 
denoted as "M," which corresponds to the ratio of flow speed and of the 
local sound velocity in the flowing fluid or fluid mixture. Since in the 
homogeneous two-phase mixtures, the sound velocity is very low, it is 
possible to achieve supersonic effects in such mixtures (with M greater 
than 1) by applying relatively low energy. 
The increase of the Mach number is obtained in conventional jets or 
turbines by increasing the flow velocity, i.e., by increasing the 
numerator of the Mach number ratio. With the apparatus disclosed in the 
parent application a supersonic effect is obtained by lowering the sonic 
speed of the Mach ratio. This allows reducing the expenditure of energy 
for achieving the supersonic effects in comparison with conventional 
systems. Note also that the intensity of a shock wave (pressure jump) is 
proportional to the square of the Mach number, i.e. the ratio of the 
pressure at the rear of the shock wave and of the pressure in front of the 
shock wave is proportional to the square of the Mach number. 
The apparatus described in the parent application comprises a nozzle 
coaxially connected to a feed line for mixing at least two fluids. An 
expansion chamber is provided downstream of the narrowest cross-sectional 
area at the outlet side of the nozzle. An outlet channel having a constant 
cross-sectional area is connected to the expansion chamber. The hydraulic 
diameter of constant cross-sectional area of the channel is as great as or 
up to three times as great as the hydraulic diameter of the narrowest 
cross-sectional area of the nozzle. Also, an outlet is connected with the 
expansion chamber and provided with a relief valve. 
In this apparatus the static pressure P.sub.ck in the rear of the shock 
wave is adjusted such that it is greater than the static pressure P.sub.l 
in front of the shock wave and is less than the half of the sum of the 
static pressure P.sub.l in front of the shock wave and of the stagnation 
pressure P.sub.o in the rear of the shock wave or is equal to the half of 
this sum. 
It is possible to achieve the desired fluid action substantially 
independently of changes of the outside pressure and end pressure. A 
stable operation with constant flow rates of the fluids in this device is 
obtained if the outer pressure or end pressure P.sub.np is greater than 
the static pressure P.sub.l, in front of the shock wave but less than the 
static pressure P.sub.ck, in the rear of the shock wave or is equal to 
this pressure P.sub.ck, wherein within these pressure ranges the pressure 
of the two-phase mixture expanded to its supersonic velocity is not 
released. 
There are certain drawbacks associated with the apparatus disclosed in the 
parent application. First, the proper ratio of fluids in the mixture and 
the pressure jump is achieved due to the geometric design of the system. 
Thus, the apparatus typically can handle only the fluids having relatively 
inflexible parameters, such as pressure and temperature. If the parameters 
of the fluids and/or the environment at the outlet of the system change, 
then a new apparatus would need to be designed and built. 
Furthermore, the apparatus disclosed in the parent application is unable to 
create a stable pressure jump if the temperature of the passive fluid is 
higher than the temperature of the active fluid, or the temperatures of 
both fluids are approximately the same. Under such conditions gas 
condenses so that it is difficult to maintain a proper ratio of the gas 
and liquid phases in the mixture such that the sonic velocity of the 
mixture is reduced as required for a stable pressure jump. Also, the 
condensation of the active fluid causes the decrease of the stagnation 
pressure of the mixture. The stagnation pressure determines the intensity 
of the pressure jump. 
As indicated, in the apparatus disclosed in the parent application, the 
intensity of the pressure jump is determined by the geometrical dimensions 
of the device and the parameters of the fluids. However, such a device 
does not provide a facility for varying the intensity of the pressure 
jump. I have invented a device which overcomes the disadvantages and 
limitations of the aforementioned apparatus. 
SUMMARY OF THE INVENTION 
According to the present invention, an improved device for acting upon 
fluids by means of a pressure jump is provided. The device consists of a 
nozzle which receives an active fluid. The passive fluid is provided to 
the nozzle such that it mixes with active fluid to form a two-phase 
mixture flowing with subsonic velocity. The passive fluid when mixed with 
the active fluid partially evaporates thereby increasing the stagnation 
pressure of the mixture and decreasing its stagnation temperature. 
An expansion chamber is joined with the nozzle where the two-phase mixture 
is accelerated. An outlet channel with constant cross-sectional area is 
connected to the expansion chamber. In the outlet channel, the mixture is 
accelerated to its supersonic velocity so as to create a pressure jump. 
The nozzle of the device comprises at least one working section and at 
least one control section. In the working section, the passive fluid is 
provided into the flow of the active fluid to create a two-phase mixture. 
In the control section, which is joined with the expansion chamber, 
additional mass is provided to the flow of the two-phase mixture so as to 
adjust the ratio of gas and liquid phases in the mixture for achieving a 
pressure jump of the desired intensity in the outlet channel. 
Since by adding mass in the control section the concentration of the phases 
can be controlled, the device of the present invention can be adjusted to 
produce a stable pressure jump of the desired intensity for the liquids 
having varying parameters without modifying the geometrical dimensions of 
the device. 
The nozzle employed in this invention is a so-called "consumption" nozzle. 
As a conventional geometrical nozzle, this nozzle is employed for 
converting potential energy into kinetic energy of the flow. More 
specifically, potential energy of pressure at the inlet of the consumption 
nozzle is converted into kinetic energy by adding mass in a subsonic fluid 
flow or by removing mass in the supersonic flow. Thus, in a consumption 
nozzle having a constant cross-section, it is possible to accelerate the 
fluid to its sonic velocity by adding mass to the flow and then to achieve 
supersonic velocity by removing mass from the flow. 
In the nozzle of this invention, the passive fluid is provided to the flow 
of the active fluid such that the stagnation pressure of the resultant 
mixture is increased and its stagnation temperature is decreased. Also 
other fluids can be provided to increase the stagnation pressure. Thus, 
the intensity of the pressure jump is enhanced by supplying mass and/or 
heat to the still on-phase fluid mixture or already two-phase fluid 
mixture flowing with subsonic velocity before coming to its sound 
velocity. 
There are known devices where the stagnation temperature of gas flow is 
reduced by introducing liquid in the flow. In a snow cannon, for example, 
snow is made by introducing water into the flow of gas, even though both 
water and gas have temperatures above zero. This phenomenon takes place 
because in a consumption nozzle a liquid evaporates thereby lowering the 
stagnation temperature of the flow and increasing its stagnation pressure. 
This phenomenon, however, has not been utilized for increasing the 
intensity of a pressure jump in a homogeneous two-phase mixture of fluids. 
Thus, the object of the present invention is to provide an apparatus which 
achieves a considerable and controllable pressure jump in a two-phase 
fluid without the drawbacks associated with the invention of the parent 
application.

DETAILED DESCRIPTION OF THE INVENTION 
In the description which follows, any reference to either direction or 
orientation is intended primarily and solely for purposes of illustration 
and is not intended in any way as a limitation of the scope of the present 
invention. Also, the particular embodiments described herein, although 
being preferred, are not to be considered as limiting of the present 
invention. Furthermore, like parts or elements in the various drawings 
hereto are generally identified by like numerals for ease of reference. 
As discussed above, the sound velocity in two-phase homogeneous flows 
(i.e., flows comprising a mixture of a gas and a liquid) is considerably 
slower than the speed of sound in a pure gas or a pure liquid. 
Accordingly, a two-phase mixture is more compressible than pure gas. 
Also as described previously, the ratio of the fluid pressures in a flow 
(at the inlet and at the outlet of the device through which the flow 
passes) is proportional to the velocity of the fluid and inversely 
proportional to its intrinsic speed of sound. This invention as an 
improvement of the invention disclosed in the parent application, which is 
incorporated herein by reference, provides that a pressure jump can be 
achieved not only by increasing the velocity of the flow, but also by 
controlling the consistency of a two-phase mixture so as to reduce the 
sonic velocity in the mixture. The pressure jump occurs when the velocity 
of the flow becomes higher than its sonic velocity. 
FIG. 1 illustrates the dependency between the speed of sound in a flow of a 
two-phase mixture and the proportion of gas and liquid in the mixture. The 
vertical axis on FIG. 1 indicates the speed of sound in the two-phase 
mixture and the horizontal axis indicates the proportion of gas and liquid 
in the mixture. More specifically on the horizontal axis at the origin 0, 
the fluid is entirely liquid and not gas, and at 1 it is gas only. The 
values in between show the proportion of gas and liquid in a homogenous 
two-phase substance. The curve denoted by .beta. shows sonic velocity in 
the mixture as a function of the volume ratio of the gas and the mixture 
of gas and liquid phases, i.e., .beta.=V.sub.g /(V.sub.g +V.sub.l) where 
V.sub.g is the volume of gas and V.sub.l is the volume of liquid in the 
mixture. The curve X shows speed of sound in the mixture as a function of 
the mass ratio of gas and the mixture of gas and liquid phases, i.e. 
X=M.sub.g /(M.sub.g +M.sub.l), where M.sub. g is the mass of gas and 
M.sub.l is the mass of liqud in the mixture. Thus, for the curve .beta., 
the horizontal axis indicates the proportion of the volumes and for the 
curve X, the horizontal axis indicates the proportion of the masses of the 
gas and liquid phases. 
Considering the curve .beta., we notice that when the volumes of gas and 
liquid phases in the mixture are approximately equal, the speed of sound 
in the two-phase mixture is minimized. Thus, when the value of .beta. is 
approximately equal to 0.5 the intensity of the pressure jump is 
maximized. In the parent application, the value of .beta. close to 0.5 was 
achieved by controlling the geometries of the fluid flow in the device of 
the parent application. 
It has been determined, however, that since in the parent application the 
appropriate value of .beta.=0.5 for producing the pressure jump was 
achieved by selecting the geometric features of the system, it was 
difficult if not impossible to adjust the apparatus of the parent 
application for changing input parameters. Furthermore, due to the fixed 
geometry of that device the intensity of the pressure jump was not 
adjustable. 
In the present invention, the ratio of the phases required for achieving 
the pressure jump is controlled not solely by the geometrical 
characteristics of the flow, but also by providing additional mass and/or 
heat into the flow. 
Referring to the curve X on FIG. 1, it depicts the relationship between the 
speed of sound in a two-phase mixture and the proportion of mass of liquid 
and gas phases in the mixture. Note that when the mass of gas is very low 
the speed of sound in the mixture is minimized. In particular, the minimum 
sonic velocity is generally achieved when the proportion of masses is 
approximately 0.000131. At this point, the speed of sound in the flow is 
at least as low as when the proportioning of the volumes (.beta.curve) is 
0.5. Thus by controlling the ratio of masses of gas and liquid phases, it 
is possible to control the value of .beta. so as to minimize the speed of 
sound in the flow for achieving the desired intensity of the pressure 
jump. 
As shown in FIG. 2, the device 10 of the present invention, has a 
cylindrical housing 12 with a converging inlet opening 14. As discussed 
subsequently, the geometry of the inlet portion 14 can be modified 
according to the properties of the fluids. The narrowest cross-section of 
the inlet 4 is joined to a cylindrical "consumption" nozzle 16. As 
indicated previously, in a consumption nozzle, if mass is supplied when 
the velocity of fluid flow is lower than the speed of sound in the fluid 
or mass is removed when the speed of the flow is higher than the speed of 
sound, the potential energy of pressure is converted to kinetic energy. 
The nozzle 16 contains a working or mixing section 18, and a control 
section 20. As described subsequently in the alternative embodiments of 
the device 10 of the present invention, the geometry of the working or 
mixing section 18 can be modified. The walls of the working or mixing 
section 18 have perforations 22. The number, size and orientation of the 
perforations or holes 22 is determined by the desired proportion of the 
active and passive fluids and the desired fluid temperature, pressure and 
concentration at the outlet of the device 10. The mixing of an active and 
a passive fluid takes place in the main mixing chamber 24. The control 
section 20 contains one or more openings 26 for providing additional 
predetermined amounts of mass and/or heat into the fluid flow to adjust 
the consistency of the resultant mixture (i.e, the value of .beta.) for 
the desired intensity of the subsequent pressure jump. 
The control section 20 is joined with an expansion chamber 28. A separation 
chamber 30 separates the control section 20 from the expansion chamber 28 
and from the working section 18. To control .beta., and thus the intensity 
of the pressure jump, one or more additional fluids are provided to the 
chamber 30 via feed line 32. These additional fluids are provided to the 
flow in the nozzle 16 via the opening(s) 26. The distance from the feed 
line 32 to the point where the nozzle 16 is joined with the expansion 
chamber 28 is approximately one radius of the nozzle 16. 
In an alternative embodiment of the present invention, the nozzle 16 may 
have a plurality of working sections 18 and/or a plurality of control 
sections 20. Generally, the portion of this device 10 located to the right 
of the chamber 28 is identical to the apparatus disclosed in the parent 
application. 
A cylindrical outlet channel 34, having a substantially constant 
cross-sectional area, is joined to the expansion chamber 28 opposite to 
the control section 20 of the nozzle 16. It is desirable for the edges at 
the transition from the expansion chamber 28 to the channel 34 to be 
smooth. A diffuser passage 36 is joined co-axially to the cylindrical 
outlet 34. 
On the outlet side of the diffuser passage 36, a cylindrical outlet socket 
38 provided with a slide valve 40 is screwed by means of a threading 
connector with the housing 12. The outlet socket 38 has a constant 
cross-sectional area with a diameter preferably equal to the outlet 
diameter of the diffuser passage 36. An inlet socket 42 that is provided 
with a slide valve 44 is screwed on the opposite end of the housing 12 by 
means of a threading connection. The cross-sectional area of the inlet 
socket 42 corresponds to that of the largest diameter of the inlet opening 
14. 
The inlet opening 14, the nozzle 16, and separation chamber 30, the mixing 
chamber 24, the expansion chamber 28, the outlet channel 34, and the 
diffuser passage 36 are all disposed in rotational symmetry with regard to 
the cylindrical housing 12 and in co-axial alignment in relation to its 
axis 46. The inlet socket 42 as well as the outlet socket 38 are also 
arranged co-axially with respect to the axis 46. 
At least one fluid feed line 48, provided with a slide valve 50, opens 
radially in the area of the working section 18 of the nozzle 16. At least 
another fluid feed line 32 having a slide valve 52 is directed towards or 
fluidly coupled with the control section 30 of the nozzle 16. An outlet 
socket 54 with a relief valve 56 opens radially into the expansion chamber 
28. 
The device 10 of the present invention can be manufactured from any 
material that would withstand the pressures, temperatures and other 
conditions required by a particular application. The inner surfaces of the 
device 10 should be substantially smooth so as to not interfere with the 
fluid flows therein. 
In summary, the device 10 of the present invention operates as follows. A 
first fluid component or an active fluid is supplied at the inlet 42 and 
then is mixed with a second fluid component or a passive fluid provided to 
the working area 18 of the nozzle 16 via the feedline 48. After the active 
and passive fluids are mixed, the velocity of the mixture becomes 
subsonic, even if the active fluid was supplied with a supersonic 
velocity. Also after the fluids are mixed the stagnation temperature of 
the mixture is decreased and its stagnation pressure is increased. In the 
control section 20, another one or more fluids are supplied so as to 
adjust the mixture's .beta. for the desired intensity of the pressure 
jump. In the expansion chamber 28, the fluids are accelerated such that 
they reach supersonic velocity in the outlet 34 where the pressure jump of 
the desired intensity occurs. 
More specifically as shown in FIG. 3, the device 10 of the present 
invention is typically connected or fluidly coupled to a fluid system that 
requires at the outlet of the device a mixture of fluids with the desired 
characteristics, such as pressure, temperature, and concentration. 
Initially, in the system 58 that incorporates the device 10, the valves 
52, 50, 44 and 40 are closed. The system 58 is activated by opening the 
valves 50 and 40, whereby the second fluid component or passive fluid is 
passed through the feed line 48 and through the perforations 22 in the 
walls of the working section 18 of the nozzle 16. From the nozzle 16 the 
fluid is provided to the expansion chamber 28. If the counter or back 
pressure in the system 58 (i.e. the pressure at the outlet 38) is greater 
than the pressure in the expansion chamber 28, relief valve 56 of an 
outlet socket 54 opens. 
The valve 56 closes after the active fluid is provided by opening the slide 
valve 44. In the working section 18 of the nozzle 16 the active and 
passive fluids mix. From the nozzle 16 the mixture is provided to the 
expansion chamber 28 and then to the cylindrical outlet channel 34, 
diffuser passage 36 and cylindrical outlet socket 38 and the opened slide 
valve 40. 
The same passive fluid (and/or other fluids) is also provided via feedline 
32 to the separation chamber 30 and then to the control section 20 of the 
nozzle 16 via the opening(s) 26. More specifically, at a distance which is 
approximately a radius of the nozzle before the expansion chamber the 
pressure of the mixture drops to the pressure of the system and at that 
point additional fluid(s) are provided. In the control section the added 
fluid(s) are mixed with the main fluid flow in the nozzle. 
By adjusting the valve 52, the supply of the additional fluid(s) through 
that valve is controlled so as to ensure the proper ratio of the phases of 
fluids in order to achieve a pressure jump of the required intensity. As 
indicated the intensity of the pressure jump is determined by the value of 
.beta.. Thus, if it is necessary to change the intensity of the pressure 
jump during the stable operation of the device, the temperature or 
pressure of the fluids in the separating chamber 30 can be changed by 
adjusting the valve 52, i.e by changing the supply of the additional mass. 
In the control section or chamber 20 the pressure of the mixture drops 
because mass is added into the flow and the pressure of the flow is 
employed for accelerating the mixture. 
According to the present invention, the proper consistency of the mixture 
required for achieving the pressure jump is produced in the control 
section 20 and working section 18 of the nozzle 16, which replaced the 
conically tapered nozzle and the diaphragm of the invention set forth in 
the aforementioned parent application. As discussed previously, the 
apparatus of the parent application employed the geometric properties of 
the apparatus to achieve the pressure jump. Since the geometry of the 
manufactured apparatus cannot be changed, an unstable condition, i.e. a 
condition when the pressure jump sometime does not occur, may arise when 
the velocity of the flow is approximately the same as the speed of sound 
in the flow due to a misadjusted value of .beta.. 
However, in the device 10 of the present invention, the value of .beta. can 
be controlled so as to maintain a stable pressure jump of the desired 
intensity. In the present invention, when the value of .beta. becomes too 
large, cool fluid can be added to the control section 20 to stabilize the 
jump. If .beta. becomes too low, its value can be increased by adding a 
hot fluid into the flow. Thus, according to the present invention, even if 
the input parameters differ from the parameters for which the device 10 
was designed, the device 10 can be adjusted for stable operation, which 
was impossible in the apparatus described in the parent application. 
The operation of the device 10 of the present invention is illustrated in 
the examples discussed below in connection with FIGS. 4, 5, 6 and 7. In 
each of these Figures, the device 10 is illustrated schematically. The 
corresponding flow velocity W and the static pressure P of the fluids (or 
the mixture) are illustrated in the axal direction of the device 10. 
In FIG. 4, the first example illustrates the operation of the device 10 of 
this invention in a system 58 for heating of buildings and structures with 
hot water. In a tall building, where the pressure of water circulating in 
the building is high, to conserve energy, the pressure of steam employed 
for circulating the water should be lower than the pressure of water. 
Thus, such a system 58 requires that the pressure of steam (active fluid) 
at the inlet of the device is lower than the pressure of water (passive 
fluid) in the system 58. In other words, the pressure of the active fluid 
at the inlet 42 is less than the pressure of the passive fluid provided 
via the feed line 48 and the pressure of hot water (the resultant mixture) 
at the outlet 38 should be maintained several times higher than the 
pressure of steam (active fluid) at the inlet 42. Also in such a system 
58, the pressure at the outlet 38 should be higher than the pressure of 
water in the building (i.e., the pressure at the feedline 48) by the value 
approximately equal to the friction and local resistance of the system 58. 
The operation of the system 58 under the conditions described above is 
illustrated in FIG. 4. The device 10 is illustrated schematically. The 
velocity of the flow W and the static pressure P are illustrated below the 
device 10. In this illustration of FIG. 4, the opening 14 is located 
between the cross-sections I and II, the working section 18 of the nozzle 
16 is located between the cross-sections II and III, the control section 
20 is between the cross-sections III and IV, the expansion chamber 28 is 
between the cross-sections IV and V, the channel 34 is between the 
cross-sections V and VI and the passage 36 is between the cross-sections 
VI and VII. 
The pressure of steam provided at the inlet 14 is lowered between the 
cross-sections I and II, where the flow path narrows. Consequently, the 
velocity of steam increases in this interval. As well known, when the flow 
path narrows, the velocity of a fluid flow increases and its pressure and 
temperature decrease. 
The passive fluid is mixed with the active fluid in the working section 18 
of the nozzle 16 between the cross-sections II and III. After mixing with 
active fluid in the initial zone of the working section 18 of the nozzle 
16 (where the pressure of the active fluid has been reduced), the passive 
fluid partially evaporates (boils). Also in this region of the nozzle 16 
where the pressure has been lowered, the heat exchange and the exchange of 
the speed components of the active and passive fluids takes place. 
Due to the evaporation of the passive fluid, additional steam is created 
thereby increasing the amount of the active fluid. Since evaporation 
converts heat into the kinetic energy of the flow, the kinetic energy of 
the flow and its stagnation pressure increase, and the stagnation 
temperature of the flow is decreased. Thus, the passive fluid also 
supplies energy into the fluid flow and contributes to the increase of the 
stagnation pressure of the flow. 
During the further motion of the mixture in the working section 18 of the 
nozzle 16, the passive fluid is continuously provided through the 
perforations 22 in the walls of the working section 18, thereby increasing 
the pressure of the mixture (due to the evaporation), and decreasing the 
velocity of the flow. The velocity of the flow becomes homogenous 
throughout the cross-section of the nozzle 16 approximately at the 
cross-section IV, prior to the point where additional fluid(s) can be 
provided from the separation chamber 30. 
In the control section 20 of the nozzle 16 located between the cross 
sections III and IV, an additional passive fluid and/or one or more other 
fluids can be supplied into the flow. These additional fluid(s) are 
supplied so as to create a two-phase mixture which has the appropriate or 
desired proportion of gas and liquid for the desired intensity of the 
subsequent pressure jump. To intensify the jump the value of .beta. has to 
be reduced. As illustrated in FIG. 1 the proportion of the masses X of gas 
and liquid effects the value of .beta. (the proportion of the volumes). 
Thus, the amount and the temperature of the additional fluid added between 
the cross sections III and IV is selected so as to adjust the value of 
.beta. for the stable pressure jump of the desired intensity. The 
selection of the appropriate parameters is apparent from FIG. 1. 
Note that the feedline 32 of the control section 20 can be connected via a 
valve (not shown) to receive fluids from the feedline 48 or from the 
outlet 40. For example, if .beta. in the area of the cross section VI is 
greater than desired, then to lower the volume of steam, a fluid, which is 
cooler than the fluid at the outlet of the system, can be supplied from 
the feed line 48 into the feed line 52. If it is necessary to supply hot 
fluid to increase .beta., feedline 52 can be connected to the outlet 40. 
The mixture moves along the nozzle 16, i.e., from the cross-section II to 
the cross-section IV with a velocity which is lower than its intrinsic 
velocity of sound since, after the passive fluid is introduced, the 
intrinsic velocity of sound of the mixture drops lower than the velocity 
of the fluid flow. This is significant since in a "consumption" nozzle, if 
mass is supplied when the velocity of the fluid flow is lower than the 
velocity of sound in the fluid, the potential energy of pressure is 
converted into kinetic energy. As noted, the movement of the fluid along 
the nozzle 16 causes the decrease of the stagnation temperature and 
therefore the increase of the stagnation pressure. 
After the cross-section IV, in the expansion chamber 28, due to the 
expanded cross-section of the flow, the pressure of the mixture and the 
intrinsic speed of sound are lowered due to the evaporation of the fluid. 
After the cross-section IV the velocity of the flow increases such that 
between the cross-sections V and VI in the channel 34, the speed of the 
flow becomes higher than the speed of sound in the mixture. For this 
reason the pressure jump occurs between the cross-sections V and VI. After 
the pressure jump, the flow velocity drops drastically. The intensity of 
the pressure jump between the cross-sections V and VI is intensified due 
to the increase of the stagnation pressure of the mixture in the nozzle 
16. As indicated previously, the stagnation pressure in the nozzle 16 is 
increased because the passive fluid evaporates, and its energy is 
converted into potential energy. 
The second example or alternative embodiment is discussed in connection 
with FIG. 5. In this example the geometry of the inlet portion 
(cross-sections I-III) of the device 10 has been modified such that the 
inlet portion widens between the cross-sections II-III. Otherwise, 
cross-sections III-VIII correspond to the beginning of the working section 
18, the control section 20, the expansion chamber 28, the channel 34, the 
diffuser 36 and the outlet 38 respectively. 
In this embodiment, the device 10 of this invention operates in connection 
with a system 58 where the pressure of steam (active fluid) at the inlet 
42 is higher than the pressure of the passive fluid provided through the 
feedline 50, and the temperature of both active and passive fluids is 
high. This situation occurs when the device 10 is utilized as a feeding 
pump of a boiler. For example, in such a system 58, the steam in the 
boiler is employed for supplying the boiler with additional water, i.e the 
steam from the boiler is used to move the condensed water in the system 
back into the boiler. A pump, which is the device 10 of this invention, 
provides water to the boiler from the source which has high temperature 
and the steam circulating in the system acts as active fluid. In such a 
system the pressure of steam (active fluid) is greater than the pressure 
of water (passive fluid). 
Initially the pressure of steam is great. In order to lower the pressure of 
steam entering the device 10 below the pressure of the water, the steam is 
expanded in the supersonic geometrical nozzle between the cross-sections I 
and III. After the passive fluid is provided to the working section 18 of 
the nozzle 16 between the cross-sections III and IV and mixed with the 
active fluid, the velocity of the flow decreases to its intrinsic subsonic 
velocity and remains subsonic at least until the cross-section V. 
Otherwise the fluid flows in the device 10 behave as described in 
connection with the previous example as shown in FIG. 4. 
If the pressure in the nozzle 16 begins to rise between the cross-sections 
III and IV so that it prevents the supply of the sufficient amount of the 
passive fluid, the nozzle 16 can be implemented as a converging cone, as 
illustrated in connection with the subsequent example of FIG. 6. 
Also in the first example of FIG. 4, the pressure of steam (active fluid) 
was low and the pressure of water (passive fluid) was great. Since in the 
first example, the pressure of steam was lower than the pressure of water, 
there was no need to reduce the pressure of steam substantially. In the 
example of FIG. 5, however, the pressure of steam is high so that it has 
to be expanded to a greater extent to reduce its pressure before the water 
is supplied. 
In the next example, discussed in connection with FIG. 5, the device 10 is 
utilized when the active fluid is water (not steam), and the temperature 
of the active fluid is higher than the temperature of the passive fluid. 
For example, the temperature of the active fluid is in the range of 
290.degree.-310.degree. and its pressure is 120-140 bars while the passive 
fluid has a somewhat lower pressure and a temperature in the range of 
about 260.degree.-270.degree.. 
In the embodiment of the invention illustrated in FIG. 6, the active fluid 
is provided via a narrow opening (cross-sections I-II) and the 
cross-section of the nozzle 16 converges (from the cross-section II to the 
cross-section VI). Since hot liquid (active fluid) flows through the 
narrow opening, its pressure is drastically reduced at the cross-section 
II such that it is lower than the pressure of boiling of the active fluid 
at a given temperature. Also at this point the velocity of the active 
fluid rises to its sonic velocity. The passive fluid, which enters the 
working section (located between the cross-sections II-III) of the nozzle 
16 (see FIG. 2), partially boils and exchanges motion components with the 
active fluid. After mixing with the passive fluid, the velocity of the 
mixture becomes subsonic. During the further motion of the mixture in the 
nozzle 16 the stagnation temperature drops and the related stagnation 
pressure rises. 
In this embodiment the nozzle 16 has a conical shape as illustrated in FIG. 
6 so that the increasing of the static pressure in the nozzle 16 does not 
inhibit the supply of the passive fluid. Otherwise, the processes that 
take place in the example of FIG. 6 from the cross-section III to the 
cross-section VII, are as described in conjunction with the first example 
shown in FIG. 4. 
The last example of FIG. 7 illustrates a way of achieving a pressure jump 
in the device 10 which was considerably simplified. In essence it 
comprises only a conical working section 18 of the nozzle 16 located 
between the cross-sections II and III, and a portion having a constant 
cross section located between the cross-sections III and IV. In this 
embodiment the pressure jump is achieved between the cross-sections III 
and IV, without using the expansion chamber 28 or the outlet channel 
(i.e., without using a portion of the device between the cross-sections IV 
and VI). In this embodiment the device 10 is useful as for example a pump 
that does not require the precise parameters of the mixture at the outlet 
and it is not necessary to control the intensity of the pressure jump. 
As illustrated between the cross-section of II and III the pressure of the 
mixture constantly drops. By selecting the proportions of the fluids 
properly, the speed of sound between these cross-sections drops such that 
the two-phase mixture becomes supersonic when it crosses the cross-section 
III. Thus, between the cross-sections III and IV, which is the channel of 
a constant cross-section, the pressure jump takes place. As in the 
previous examples of FIGS. 4, 5 and 6, in the working section 18 of the 
nozzle 16 the stagnation temperature is reduced and the stagnation 
pressure is increased. 
It should be noted that in the geometrical method of effecting the pressure 
jump as described in the parent application, it is difficult to ensure the 
stable operation of the device 10 with low volumes of flow of the mixture, 
for example, less than 500 liters per hour. Such stable operation with the 
apparatus of the parent application is difficult since the dimensions that 
are required for the formulation of the pressure jump become very small, 
i.e., fractions of millimeters. This drawback is easy to remedy by using 
the device 10 of the present invention since the pressure jump can be 
controlled by adding mass in the control section 20. It is also 
significant that, as indicated, the variation of the parameters at the 
outlet of the device 10 does not effect the throughput of the device 10. 
Thus from the analysis discussed in connection with FIG. 1, by employing 
the consumption nozzle 16, it is possible not only to control the 
magnitude of the pressure jump, but also to ensure the precise 
concentration of each of the fluids that are mixed in the device 10. 
Accordingly, the device 10 of the present invention can be advantageously 
employed for adjusting the doses of the mixture. 
In summary, it should be noted that the method of effecting the pressure 
jump in a transonic flow of a diffused mixture of fluids by effecting the 
stagnation pressure prior to the pressure jump has wide applications. The 
ability to reduce the stagnation temperature in the flow of the mixture 
which is accompanied by the increase of the stagnation pressure, under the 
second law of thermodynamics, implies a more efficient conversion of the 
heat energy into work. A practical implication is that given the same 
parameters of the fluids at the inlet of the device 10 and the 
"consumption" influence (i.e., the addition of mass) on the flow of a 
diffused mixture one can obtain higher throughput of the mixture and/or 
the higher pressure at the outlet of the device in comparison to the 
purely geometrical design of the parent application. This is obtained due 
to the high compressibility of the homogenous diffused mixtures, as well 
as due to the specific characteristic of the dependency between the 
velocity of sound in the flow of a diffused mixtures and the mass, which 
dependency has a very sharp minimum at very low values of X. 
Although the preferred embodiments of the present invention employ a direct 
cycle, the device 10 is also applicable to systems 58 employing a reverse 
cycle which will enable the effective utilization of the invention in 
systems related generally to air conditioning and cooling. 
Variations of the above-described device 10 which involved minor changes 
are clearly contemplated to be within the scope of the present invention. 
In addition, minor variations in the design, angles or materials of the 
various components of the device 10 are also contemplated to be within the 
scope of the present invention. These modifications and variations may be 
made without departing from the spirit and scope of the present invention, 
as will become apparent to those skilled in the art. The specific 
embodiments described herein are offered by way of example only, and the 
invention is limited only by the terms of the appended claims.