CN116907125A - Low-pressure refrigerant distributor and falling film evaporator of same - Google Patents
Low-pressure refrigerant distributor and falling film evaporator of same Download PDFInfo
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- CN116907125A CN116907125A CN202310869733.8A CN202310869733A CN116907125A CN 116907125 A CN116907125 A CN 116907125A CN 202310869733 A CN202310869733 A CN 202310869733A CN 116907125 A CN116907125 A CN 116907125A
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- 239000003507 refrigerant Substances 0.000 title claims abstract description 90
- 239000011552 falling film Substances 0.000 title claims abstract description 59
- 239000007788 liquid Substances 0.000 claims abstract description 237
- 238000009826 distribution Methods 0.000 claims abstract description 118
- 238000000926 separation method Methods 0.000 claims description 12
- 230000002706 hydrostatic effect Effects 0.000 claims description 6
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- 239000006260 foam Substances 0.000 claims description 3
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 230000003068 static effect Effects 0.000 abstract description 4
- 238000005057 refrigeration Methods 0.000 abstract description 2
- 239000012071 phase Substances 0.000 description 7
- 239000004744 fabric Substances 0.000 description 6
- 230000001965 increasing effect Effects 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000009827 uniform distribution Methods 0.000 description 2
- LVGUZGTVOIAKKC-UHFFFAOYSA-N 1,1,1,2-tetrafluoroethane Chemical compound FCC(F)(F)F LVGUZGTVOIAKKC-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
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Abstract
The invention discloses a low-pressure refrigerant distributor and a falling film evaporator of the distributor, and belongs to the technical field of refrigeration air conditioners. The axial distribution box is installed in the liquid distribution box through a plurality of supporting structures, the supporting structures are arranged at equal intervals along the axial direction of the liquid distribution box and used for axially dividing refrigerant liquid in the liquid distribution box into a plurality of equidistant cells, and the supporting structures can be used for supporting the axial distribution box. Compared with the prior art, the gas-liquid separator can effectively reduce the air flow resistance, can reduce the diameter of the cylinder by about 10 percent under the condition of keeping the same flow resistance, effectively reduces the cost of the evaporator, and ensures that the static pressure of the refrigerant in the axial flow is kept unchanged by the conical axial distribution box, so that the non-uniformity of the axial flow distribution is kept below 10 percent. The gas-liquid separator and the conical distribution box can effectively reduce the refrigerant filling amount, and can reduce the refrigerant filling amount of the falling film evaporator by about 15 percent.
Description
Technical Field
The invention relates to a low-pressure refrigerant distributor and a falling film evaporator of the distributor, and belongs to the technical field of refrigeration air conditioners.
Background
The falling film evaporator of low pressure refrigerant includes one casing; a heat exchange tube bundle; a refrigerant gas-liquid separator and distributor at the top of the housing, and a gas outlet at the top of the housing. The gas-liquid two-phase refrigerant enters the shell from the top of the shell, is separated into gas and liquid in the gas-liquid separator, the liquid refrigerant flows through the tube bundle from top to bottom after being distributed into the shell side by the distributor, absorbs heat and boils, and steam flows out of the evaporator from an outlet at the top of the shell. The gas separated by the gas-liquid separator also flows out of the evaporator from the top outlet of the housing. The water flows on the tube side of the heat exchange tube bundle, transferring heat to the refrigerant on the shell side and then the water temperature drops, resulting in cold water required for air conditioning (e.g., refrigerant distributor for falling film evaporator as disclosed in publication No. CN109642760 a).
Compared with a flooded evaporator (such as a flooded evaporator shown in the publication No. CN 211204506U), the shell side refrigerant level of the falling film evaporator is low, so that on one hand, the filling amount of the refrigerant is effectively reduced; on the other hand, the hydrostatic column pressure of the refrigerant liquid is reduced, and the heat exchange temperature difference between the shell side refrigerant and the tube side water is increased. The saturation temperature of the low pressure refrigerant is sensitive to pressure, for example, the saturation temperature of the low pressure refrigerant R1233zde varies by about 0.4 ℃ per 1kPa pressure change at 6 ℃, the saturation temperature of the medium pressure refrigerant R134a varies by 0.1 ℃, thus reducing the hydrostatic column pressure of the refrigerant liquid is of great importance to the heat exchange performance of the low pressure refrigerant evaporator, and reducing the flow pressure drop of the refrigerant gas within the evaporator is also a key to the successful design of the low pressure refrigerant evaporator.
Patent 215063028U discloses a distributor and a falling film evaporator comprising the same, and proposes a distributor design of the falling film evaporator. The distributor comprises a primary distributor and a secondary distributor, wherein the primary distributor is a gas-liquid separation cavity and is arranged along the length of the evaporator. A plurality of porous plates are arranged in the separation cavity along the flow direction, so that disturbance of axial flow of the refrigerant is reduced, and gas-liquid separation is promoted. Small holes are uniformly distributed on the bottom plate of the gas-liquid separation cavity, and separated liquid falls into the secondary separator through the small holes. The secondary distributor is a liquid distribution box with an opening at the top and small holes uniformly distributed at the bottom, and the liquid in the liquid distribution box is uniformly distributed on the tube bundle below the distributor through the small holes. The design has no special refrigerant axial distributor, and the liquid level in the gas-liquid separation cavity is uneven along the length direction under the low-load working condition, so that the uniformity of refrigerant distribution along the length of the tube can be influenced, and the heat exchange performance of the evaporator under the low load is reduced.
Patent 105518391a discloses an integrated separator-distributor for a falling film evaporator, which proposes a separator and distributor design for a falling film evaporator. The separator has 2 schemes, wherein the refrigerant in scheme 1 enters from the middle of the gas-liquid separator and then flows towards two ends, and the refrigerant in scheme 2 enters from one end of the separator and flows towards the other end of the separator. The liquid refrigerant after gas-liquid separation flows into an axial distributor having a fixed cross-sectional shape in the axial direction. The refrigerant gas separated by the gas-liquid separator is directed through the vent stack to near the bottom refrigerant level. The axial distributor of this design is because the flow area is fixed along the flow direction, and simultaneously, because the refrigerant flows the in-process along the axial to the other end from the entrance point, the velocity of flow gradually reduces, along the hydrostatic pressure of axial rising, be unfavorable for axial refrigerant distribution's homogeneity, the ventilation standpipe of design is with the refrigerant liquid level of gaseous (entrained some liquid drops) guide to the bottom, and the pipeline is too long on the one hand consumes the material, on the other hand has also blockked up the partial air current passageway of evaporimeter lower part, has increased the flow pressure drop. In addition, the gas outlet of the evaporator designed by the patent is arranged on the side surface of the evaporator cylinder body, and the gas outlet is close to the liquid level at the bottom, so that the full separation of liquid drops entrained in steam is not facilitated, the suction liquid carrying of a compressor is easily caused, and the performance of a refrigerator is reduced.
Patent 109642760a discloses a refrigerant distributor for a falling film evaporator, and proposes a distributor design of the falling film evaporator, in which the upper surface of the refrigerant gas-liquid separator is inclined, and has a minimum height at the gas outlet position and a maximum height at the other end or both ends of the cylinder, and this design increases the flow area of the refrigerant flowing under the gas outlet, and reduces the local flow resistance of the refrigerant vapor under the gas outlet. But the length of the gas-liquid separator is similar to that of the evaporator cylinder, and the refrigerant filling amount is larger. In addition, although the height of the gas-liquid separator at the gas outlet is minimized, the separator still blocks a portion of the flow area, increasing the flow resistance.
Patent 111919075a discloses an integrated separator and distributor structure for a falling film evaporator, and proposes an integrated gas-liquid separator and distributor structure for a falling film evaporator, wherein after refrigerant is separated in the separator, liquid refrigerant directly flows into grooves from openings at both sides of the bottom of the separator, the grooves are axially arranged along the evaporator, and liquid entering the grooves flows out from a series of small holes axially arranged at the top of the groove channels, so that the grooves actually play the role of axial distributors. The invention has the advantages that the axial distribution of the refrigerant is realized through the smaller grooves, which is beneficial to reducing the refrigerant filling amount, but the groove processing is more complicated, and meanwhile, the gas-liquid separator extends below the gas outlet along the axial direction, so that part of gas flow channels are blocked. In order to reduce the flow resistance of the gas refrigerant, a larger evaporator cylinder is required to house the gas-liquid separator.
For this reason, it is necessary to design a low pressure refrigerant distributor and a falling film evaporator of the distributor to solve the above problems.
Disclosure of Invention
The invention provides a low-pressure refrigerant distributor and a falling film evaporator of the distributor, which aim to have the characteristics of low refrigerant filling quantity of a gas-liquid separator and the distributor, and the design of the invention is adopted, the refrigerant filling quantity of the falling film evaporator can be reduced by about 15 percent, the gas flow rate at the position close to the gas outlet of the evaporator is the area with the highest sensitive flow resistance, the flow resistance is reduced by increasing the flow area under the gas outlet through the design of the gas-liquid separator, or the diameter of a cylinder body can be reduced by about 10 percent under the condition of keeping the same flow resistance, the cost of the evaporator is effectively reduced, and the gas outlet guide pipe is arranged on the separator, so that refrigerant liquid carried in the gas outlet guide pipe can be effectively removed, and the liquid is prevented from flowing into a compressor through the gas outlet, thereby causing suction liquid.
The method is realized by the following technical scheme:
the utility model provides a low pressure refrigerant distributor, includes conical structure's axial distribution box and cloth liquid box, axial distribution box installs in cloth liquid box through a plurality of bearing structure, and a plurality of bearing structure follow cloth liquid box axial equidistance and arrange for with the refrigerant liquid in the cloth liquid box divide into a plurality of equidistant cells along the axial, bearing structure can be used as supporting axial distribution box, on the other hand axial distribution box's upper surface is equipped with the aperture of flowing out along the axial, and when the refrigerant liquid in the axial distribution box flows out through the aperture of flowing out and falls into cloth liquid box in, gathers after getting into a plurality of cells, the bottom surface of cloth liquid box is a perforated plate, and the refrigerant after gathering flows out through the aperture on the perforated plate.
By adopting the scheme, after the liquid enters the axial distribution box from the large end of the axial distribution box, the liquid flows along the axial direction to the other end, part of the liquid flows out from the upper surface of the axial distribution box along the axial direction, but the flow rate of the liquid along the axial direction of the axial distribution box is reduced due to the gradual reduction of the through-flow cross section area of the axial distribution box along the axial direction, so that the static pressure of the fluid is kept almost unchanged, the internal and external pressure difference of each small hole of the axial distribution box is kept unchanged, the outflow flow of each small hole is kept unchanged, and in addition, the non-uniformity of the axial distribution box along the axial direction is further reduced after the convergence of the small chambers, thereby enhancing the uniformity of the axial distribution of the refrigerant and reducing the filling amount of the refrigerant.
The falling film evaporator comprises a barrel, a first air outlet, a gas-liquid separator, a liquid inlet pipe, the axial distribution box and a liquid distribution box, wherein the first air outlet is arranged at one end of the barrel and is communicated with the interior of the barrel;
the liquid distribution box is arranged inside the cylinder body, the liquid distribution box and the axial distribution box are both positioned below the gas-liquid separator, and the bottom of the gas-liquid separator is communicated with the axial distribution box.
The cross-sectional shape of the gas-liquid separator is rectangular, but the present invention is not limited to the cross-sectional shape of the separator, and may be other shapes such as a circle, an ellipse, a curve, and the like.
Preferably, the outflow holes are uniformly distributed along the length direction of the evaporator or along the length direction of the distribution box, and the taper angle of the axial distribution box is 3-7 degrees.
Preferably, the liquid inlet pipe is an elbow pipe, and the other end of the liquid inlet pipe extends out of the cylinder body.
Preferably, two second air outlets are arranged at the other end of the gas-liquid separator, the two second air outlets are symmetrically arranged and are close to the upper part of the gas-liquid separator, gas after gas-liquid separation flows out from the second air outlets, and the liquid outlet is flush with the bottom surface of the gas-liquid separator, so that liquid outflow is facilitated.
It should be noted that a liquid baffle or a foam remover may be disposed at the air outlet of the separator to remove some droplets entrained in the air flow.
Preferably, a liquid pipe is communicated with the liquid outlet of the gas-liquid separator, and the other end of the liquid pipe extends into the liquid distribution box and is communicated with an axial distribution box in the liquid distribution box.
The end of the axial distribution box which is positioned at the liquid pipe connection is larger than the other end of the axial distribution box.
By adopting the scheme, the hydrostatic column pressure head provided by the liquid in the liquid pipe is used for overcoming the flow resistance of the refrigerant liquid in the axial distribution box.
Preferably, the falling film evaporator further comprises a tube bundle support plate, a cover plate and a heat exchange tube bundle penetrating through tube bundle support plate tube holes, wherein the tube bundle support plate, the cover plate and the heat exchange tube bundle penetrate through tube bundle support plate tube holes are respectively arranged in the cylinder, the cover plate is L-shaped, the horizontal edge of the cover plate seals the upper portion of the liquid distribution box, the vertical edge of the cover plate is clung to the side edge of the tube bundle support plate and extends downwards until exceeding the tube holes of the falling film region at the bottom of the tube bundle support plate, a notch is formed above the side panel of the liquid distribution box, a gap is further formed between the cover plate and the side panel of the liquid distribution box, and a pressure balance channel is formed by arranging the notch and the gap, so that the internal pressure of the liquid distribution box is equal to the pressure of the falling film tube bundle region, and liquid in the liquid distribution box can fall into the falling film tube bundle region by virtue of hydrostatic pressure.
The refrigerant falling into the liquid distribution box passes through the porous plate on the liquid distribution box and drops onto the falling film tube bundle through the small holes on the porous plate.
The vertical edges of the cover plate of the L-shaped structure wrap the outer side of the falling film tube bundle region, so that the gas generated by evaporation of the falling film tube bundle region can be guided to flow downwards in the same direction as the liquid drops, and the lateral flow of the gas flow is avoided, and the flow of the liquid drops can be damaged.
Preferably, the falling film evaporator further comprises a defoaming screen installed between the cylinder and the cover plate for removing liquid droplets entrained in the refrigerant gas.
In order to reduce the flow rate of the passing net, the defoaming screen is installed at a horizontal plane near the center of the cylinder or is installed obliquely, and the inclination angle is within +/-30 degrees relative to the horizontal plane.
Preferably, the falling film evaporator further comprises an air duct arranged in the cylinder, the air duct is communicated with the second air outlet of the gas-liquid separator, the other end of the air duct stretches into the lower part of the defoaming screen, the air duct is used for guiding the air flow from the gas-liquid separator and the liquid drops carried in the air duct to the lower part of the defoaming screen and mixing with the air flow generated by evaporation of the tube bundle, and then the air flow upwards passes through the defoaming screen.
By adopting the scheme, unlike the technical scheme with the publication number of CN105518391A, the air duct designed by the invention can remove entrained liquid drops only by passing through the defoaming screen at the central horizontal plane of the cylinder body, and the guide pipe is not required to be guided to the vicinity of the liquid pool at the bottom. On one hand, entrained liquid drops are effectively removed through the defoaming screen, on the other hand, the length of the air duct is reduced, the cost is saved, meanwhile, the longer air duct is prevented from blocking the air flow channel at the lower part of the evaporator, and the flow pressure drop is increased.
It is also to say that when the first air outlet is arranged near the axial middle position of the cylinder, two air-liquid separators can be arranged on two sides of the air outlet, and each air-liquid separator is provided with a liquid inlet pipe, a liquid outlet and one or two second air outlets; the liquid outlet of each gas-liquid separator is respectively connected with the two conical axial distribution boxes below through respective liquid pipes; each axial distribution box is placed in the liquid distribution box; each axial distribution box ensures the uniform distribution of the refrigerant along the axial direction, and the liquid distribution box converges the refrigerant liquid and distributes the refrigerant liquid to the falling film tube bundles below for the second time.
The beneficial effects of the invention are as follows: compared with the prior art, the gas-liquid separator designed by the invention can effectively reduce the air flow resistance, and can reduce the diameter of the cylinder by about 10 percent under the condition of keeping the same flow resistance, thereby effectively reducing the cost of the evaporator. The conical axial distribution box keeps the static pressure of the refrigerant in the axial flow unchanged, so that the non-uniformity of the axial flow distribution is kept below 10%. The gas-liquid separator and the conical distribution box can effectively reduce the refrigerant filling amount, and can reduce the refrigerant filling amount of the falling film evaporator by about 15 percent.
Drawings
FIG. 1 is a three-dimensional block diagram of a falling film evaporator in accordance with the present invention;
FIG. 2 is a longitudinal cross-sectional view of a falling film evaporator according to the present invention;
FIG. 3 is a schematic view of the axial distribution box and the liquid distribution box in the present invention;
FIG. 4 is a transverse cross-sectional view of the falling film evaporator of the present invention, wherein the evaporator cylinder is not shown;
FIG. 5 is a partial schematic view of the transverse cross-section of FIG. 4;
FIG. 6 is a schematic view of a support plate structure of a falling film evaporator, wherein heat exchange tube bundles passing through tube holes are not shown;
in the figure: 1. a gas-liquid separator; 2. a first air outlet; 3. a cylinder; 4. a defoaming screen; 5. a cover plate; 6. a liquid distribution box; 7. a tube bundle support plate; 8. an axial distribution box; 9. a support structure; 10. a liquid inlet pipe; 11. a second air outlet; 12. an air duct; 13. a liquid outlet; 14. a liquid pipe; 15. a vertical side; 16. a small outflow hole; 17. a porous plate; 18. a notch; 19. pipe holes in the liquid filling area; 20. falling film zone pipe holes; 21. the liquid level of the refrigerant liquid pool.
Detailed Description
In order to provide technical means for the invention; creating a feature; the purpose and effect of the present invention will become more apparent and the invention will be further elucidated with reference to the drawings.
As shown in fig. 1-6, a low-pressure refrigerant distributor comprises an axial distribution box 8 and a liquid distribution box 6 with conical structures, wherein the upper surface of the axial distribution box 8 is axially provided with outflow small holes 16, the bottom surface of the liquid distribution box 6 is provided with a porous plate 17, the axial distribution box 8 is arranged in the liquid distribution box 6 through a plurality of supporting structures 9, the supporting structures 9 are axially equidistantly arranged along the liquid distribution box 6 and are used for dividing the refrigerant liquid in the liquid distribution box 6 into a plurality of equidistant small chambers along the axial direction, the supporting structures 9 can be used for supporting the axial distribution box 8, and on the other hand, when the refrigerant liquid flows out from the outflow small holes 16 of the axial distribution box 8 and falls into the liquid distribution box 6, the refrigerant is converged after entering the small chambers, and the converged refrigerant flows out through the small holes of the porous plate 17.
It should be noted that the gas-phase gas content in the gas-liquid separator is calculated according to the Hughmark formula:
α＝βK H (1.1)
wherein α is the gas phase gas fraction; beta is the gas phase volume flow percentage calculated from the formula:
where x is the mass flow percentage (dryness) of the gas phase in the separator flow channels; ρ g 、ρ l Respectively the density of gas and liquid phase, kg/m 3 。
Parameter K in formula (1.1) H Is a function of the parameter Z. The parameter Z is expressed as:
wherein d is h Is the through flow of the separatorHydraulic diameter of cross section, m; mu (mu) g 、μ l The dynamic viscosity of gas and liquid phases is kg/(m.s); g is the gravitational acceleration, 9.81m/s 2 The method comprises the steps of carrying out a first treatment on the surface of the G is the mass flow rate, kg/(m) 2 ·s)：
Wherein m is the refrigerant mass flow, kg/s; a is that i Is the through flow cross section area of the separator, m 2 。
The calculation results are shown in table 1,
table 1 is a comparison of the prior art (publication No. CN 109642760A) with the present invention
Calculations indicate that the conical distributor box, together with the shortened gas-liquid separator, can reduce the evaporator charge by about 15%, as shown in table one. The first table shows the refrigerant charge that can be saved by using the 700-ton falling film evaporator designed by the technology of the invention. The falling film evaporator adopts R1233zde low-pressure refrigerant, the cylinder diameter is 1.12m, the length of the evaporator is 3.66m, the inner diameter of the air outlet is 0.58m, and the air outlet is positioned at a position which is 20% away from one end of the evaporator in the axial direction. As can be seen from Table one, compared with the prior art, the gas-liquid separator and the axial distributor of the present invention can respectively save 18kg and 30kg of refrigerant, which amounts to 15% of the evaporator charge. It should be noted that, by adopting the technology of the invention, the cylinder diameter can be reduced, and more refrigerant filling quantity can be saved.
In conclusion, the conical axial distribution box not only improves the uniformity of the distribution of the refrigerant along the axial direction, but also can reduce the filling amount of the refrigerant.
The falling film evaporator comprises a cylinder 3, a first air outlet 2, a gas-liquid separator 1, a liquid inlet pipe 10, an axial distribution box 8 and a liquid distribution box 6, wherein the first air outlet 2 is arranged at one end of the cylinder 3 and is communicated with the inside of the cylinder 3, the gas-liquid separator 1 is arranged in the cylinder 3, the first air outlet 2 extends to the other end of the cylinder 3 and is used for avoiding the space below the air outlet, the air outlet lower gap is increased, the air flow resistance is reduced, one end of the liquid inlet pipe 10 extends into the gas-liquid separator 1 and corresponds to one end face of the gas-liquid separator 1, a refrigerant enters the gas-liquid separator 1 through the liquid inlet pipe 10 and then is sprayed on the end face of the gas-liquid separator 1, then flows reversely, and liquid flows out from a liquid outlet 13 at the other end of the gas-liquid separator 1.
The liquid distribution box 6 is arranged inside the cylinder body 1, the liquid distribution box 6 and the axial distribution box 8 are both positioned below the gas-liquid separator 1, and the bottom of the gas-liquid separator 1 is communicated with the axial distribution box 8.
The liquid inlet pipe 10 is an elbow, and the other end of the liquid inlet pipe 10 extends out of the cylinder 3.
Two second air outlets 11 are arranged at the other end of the gas-liquid separator 1, the two second air outlets 11 are symmetrically arranged and are close to the upper part of the gas-liquid separator 1, gas after gas-liquid separation flows out from the second air outlets, and the liquid outlet 13 is flush with the bottom surface of the gas-liquid separator 1, so that liquid outflow is facilitated.
The liquid outlet 13 of the gas-liquid separator 1 is communicated with a liquid pipe 14, and the other end of the liquid pipe 14 extends into the liquid distribution box 6 and is communicated with the axial distribution box 8 in the liquid distribution box 6.
The outflow apertures 16 are uniformly distributed along the length of the evaporator cylinder 1 or along the length of the axial distributor box 8, the conical angle of the axial distributor box 8 being 3-7 °.
The falling film evaporator further comprises a tube bundle support plate 7, a cover plate 5 and a heat exchange tube bundle (not shown in the figure) penetrating through tube holes of the support plate, wherein the tube bundle support plate 7, the cover plate 5 and the heat exchange tube bundle penetrate through tube holes of the support plate, the cover plate 5 is L-shaped, the horizontal edge of the cover plate 5 seals the upper part of the liquid distribution box 6, the vertical edge 15 of the cover plate 5 is tightly attached to the side edge of the tube bundle support plate 7 and extends downwards until exceeding the tube holes 20 of a falling film area at the bottom of the tube bundle support plate 7, a notch 18 is formed above a side panel of the liquid distribution box 6, a gap is further formed between the cover plate 5 and the side panel of the liquid distribution box 6, and the gap is used for forming a pressure balance channel by arranging the notch 18 and the gap, so that the internal pressure of the liquid distribution box 6 is equal to the pressure of the falling film tube bundle area, and liquid in the liquid distribution box can fall down to the falling film tube bundle area by virtue of liquid column static pressure.
Heat exchange tube bundles (not shown) are penetrated in tube holes in the tube bundle supporting plate and are divided into an upper part and a lower part. The upper tube bundle is called a falling film heat exchange tube bundle, the lower tube bundle is called a flooded heat exchange tube bundle, the shell side area where the falling film heat exchange tube bundle is located is called a falling film tube bundle area, and the shell side area where the flooded heat exchange tube bundle is located is called a flooded tube bundle area. It should be noted that, below the falling film evaporator cylinder 1, there is a refrigerant liquid pool, and the liquid level of the liquid pool is generally at the top position of the flooded tube bundle area, as shown by the wavy line in fig. 6.
The falling film evaporator further comprises a defoaming screen 4 installed between the cylinder 1 and the cover plate 5 for removing liquid drops entrained in the refrigerant gas.
The falling film evaporator further comprises an air duct 12 arranged in the cylinder, the air duct 12 is communicated with the second air outlet 11 of the gas-liquid separator 1, the other end of the air duct extends into the lower part of the defoaming screen 4 and is used for guiding the air flow from the gas-liquid separator and the liquid drops carried by the air duct to the lower part of the defoaming screen 4, mixing the air flow with the air flow generated by evaporation of the tube bundle and then passing through the defoaming screen 4 upwards.
Here, the first air outlet 2 is communicated with an external compressor, droplets entrained by the upward air flow are separated, collected and dropped back into a liquid pool below the cylinder 1 by the defoaming screen 4, and the air enters the external compressor through the air outlet 2 upwards.
It should be noted that, the two-phase mixture enters the barrel from the feed liquor pipe, under the guidance of the feed liquor pipe, flows to one end face of the gas-liquid separator first, then flows to the other side of the gas-liquid separator reversely, and gas-liquid separation is performed by utilizing the length of the gas-liquid separator, and meanwhile, the reverse flow is also helpful for gas-liquid separation: the section size of the gas-liquid separator needs to meet the following requirements:
wherein Fr g Is the gas phase Froude number;
the length of the gas-liquid separator is not less than 8 times of the hydraulic diameter d of the through flow section h ,m。
As another embodiment, when the first air outlet 2 is arranged near the axial middle position of the cylinder 1, two air-liquid separators 1 can be arranged on two sides of the air outlet 2, and each air-liquid separator 1 is provided with one liquid inlet pipe 10, one liquid outlet 13 and one or two second air outlets 11; the liquid outlet 13 of each gas-liquid separator 1 is respectively connected with the lower two conical axial distribution boxes 8 through respective liquid pipes 14; each axial distribution box 8 is placed inside the liquid distribution box 6; each axial distribution box 8 ensures the uniform distribution of the refrigerant along the axial direction, and the liquid distribution boxes 6 collect the refrigerant liquid and then distribute the refrigerant liquid to the falling film tube bundles below for the second time.
The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be appreciated by persons skilled in the art that the present invention is not limited to the embodiments described above, but is capable of numerous variations and modifications without departing from the spirit and scope of the invention as hereinafter claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (8)
1. A low pressure refrigerant dispenser, characterized by: the axial distribution box comprises a conical structure and a liquid distribution box, wherein the axial distribution box is arranged in the liquid distribution box through a plurality of supporting structures, the supporting structures are axially equidistantly arranged along the liquid distribution box and used for axially dividing refrigerant liquid in the liquid distribution box into a plurality of equidistant cells, the supporting structures can be used for supporting the axial distribution box, on the other hand, the upper surface of the axial distribution box is axially provided with outflow small holes, when the refrigerant liquid in the axial distribution box flows out through the outflow small holes and falls into the liquid distribution box, the refrigerant liquid is converged after entering the plurality of cells, the bottom surface of the liquid distribution box is a porous plate, and the converged refrigerant flows out through the small holes on the porous plate.
2. The falling film evaporator is characterized by comprising a barrel, a first air outlet, a gas-liquid separator, a liquid inlet pipe, an axial distribution box and a liquid distribution box, wherein the first air outlet is arranged at one end of the barrel and is communicated with the interior of the barrel;
the liquid distribution box is arranged inside the cylinder body, the liquid distribution box and the axial distribution box are both positioned below the gas-liquid separator, and the bottom of the gas-liquid separator is communicated with the axial distribution box.
3. A falling film evaporator according to claim 2, wherein: the outflow small holes are uniformly distributed along the length direction of the cylinder body of the evaporator or along the length direction of the distribution box, and the taper angle of the axial distribution box is 3-7 degrees.
4. A falling film evaporator according to claim 2, wherein: two second gas outlets are arranged at the other end of the gas-liquid separator, the two second gas outlets are symmetrically arranged and are close to the upper part of the gas-liquid separator, gas after gas-liquid separation flows out from the second gas outlets, and the liquid outlet is flush with the bottom surface of the gas-liquid separator, so that liquid outflow is facilitated.
5. A falling film evaporator according to claim 4 wherein: the liquid outlet of the gas-liquid separator is communicated with a liquid pipe, and the other end of the liquid pipe extends into the liquid distribution box and is communicated with an axial distribution box in the liquid distribution box.
6. A falling film evaporator according to claim 5 wherein: the liquid distributor is characterized by further comprising a tube bundle supporting plate, a cover plate and a heat exchange tube bundle penetrating through tube holes of the tube bundle supporting plate, wherein the tube bundle supporting plate, the cover plate and the heat exchange tube bundle penetrate through tube holes of the tube bundle supporting plate are respectively arranged in the cylinder body, the cover plate is L-shaped, the horizontal edge of the cover plate seals the upper part of the liquid distribution box, the vertical edge of the cover plate is clung to the side edge of the tube bundle supporting plate and extends downwards until exceeding the tube holes of a falling film area at the bottom of the tube bundle supporting plate, a gap is formed above a side panel of the liquid distribution box, a gap is further formed between the cover plate and the side panel of the liquid distribution box, and the gap are used for forming a pressure balance channel so as to keep the internal pressure of the liquid distribution box equal to the pressure of the falling film tube bundle area by virtue of hydrostatic pressure of liquid in the liquid distribution box.
7. A falling film evaporator according to claim 6 wherein: and a defoaming screen is arranged between the cylinder body and the cover plate and is used for removing liquid drops entrained in the refrigerant gas.
8. A falling film evaporator according to claim 7 wherein: the foam removing device also comprises an air duct arranged in the cylinder body, the air duct is communicated with a second air outlet of the air-liquid separator, the other end of the air duct extends into the lower part of the foam removing silk screen, the air flow from the gas-liquid separator and the liquid drops carried by the air flow are guided to the lower part of the defoaming screen by the air duct, are mixed with the air flow generated by evaporation of the tube bundle, and then pass through the defoaming screen upwards.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310869733.8A CN116907125A (en) | 2023-07-14 | 2023-07-14 | Low-pressure refrigerant distributor and falling film evaporator of same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310869733.8A CN116907125A (en) | 2023-07-14 | 2023-07-14 | Low-pressure refrigerant distributor and falling film evaporator of same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116907125A true CN116907125A (en) | 2023-10-20 |
Family
ID=88364234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310869733.8A Pending CN116907125A (en) | 2023-07-14 | 2023-07-14 | Low-pressure refrigerant distributor and falling film evaporator of same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116907125A (en) |
-
2023
- 2023-07-14 CN CN202310869733.8A patent/CN116907125A/en active Pending
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