A subcritical flow vortex heat exchanger

Abstract

The present invention discloses a subcritical flow vortex heat exchanger, comprising an exchanger shell, an air inlet nozzle extending horizontally and connected to the top of the exchanger shell, a cold-end gas outlet centrally located at the left end of the exchanger shell, and a hot-end gas outlet centrally located at the right end of the exchanger shell. The exchanger shell is generally in the shape of a long tube, and a heat exchange core tube is coaxially installed in the middle right part of the cavity. The heat exchange core tube divides the inner and outer inner cavities of the exchanger shell into an energy separation zone and a cooling water zone. The left cavity of the exchanger shell is connected to the air inlet nozzle and serves as a gas vortex flow zone for the high-pressure and high-temperature gas entering tangentially to form a high-speed vortex flow. The hot-end gas outlet is used to guide out the low-temperature and high-pressure gas-liquid mixed state condensed after the heat transfer of the outer high-temperature gas. The cold-end gas outlet is provided with a cold steam guide pipe, which is used to guide out the low-temperature and low-pressure gas-liquid mixed state condensed after the energy of the inner low-temperature gas is exchanged with the outer high-temperature gas. The heat exchanger has the advantages of stronger heating capacity, low pressure ratio, high-temperature hot water, high heating energy efficiency ratio, and high heat transfer efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchangers, and in particular relates to a subcritical flow vortex heat exchanger. Background Art

[0002] In modern society, a large amount of low-temperature waste heat exists, such as heat dissipation in communication data centers, power generation cold-ends, and other industrial processes. This low-temperature heat is essentially dissipated into ambient heat sinks, resulting in significant energy waste. Direct reuse of this low-temperature heat is difficult, and often requires the necessary technical means, methods, and devices to collect, concentrate, and process it into high-temperature, high-quality heat for wider application.

[0003] like Figure 3 As shown, the existing heat pump heat energy recovery process mainly adopts a single-stage compression system, that is, evaporator A absorbs heat at low temperature → compressor B high pressure → condenser C releases heat at high temperature → expansion valve D is low temperature and low pressure → then returns to the evaporator to absorb heat at low temperature for a single-stage cycle, so as to achieve the purpose of collecting, concentrating and processing low-temperature thermal energy into high-temperature thermal energy. However, the single-stage compression system is difficult to obtain high-temperature heating capacity under low pressure ratio, and generally can only be below 50°C, resulting in limited application value and scope of low-temperature thermal energy recovery.

[0004] In order to obtain a higher temperature of the water supply, such as Figure 4 As shown, a bipolar compression system is currently used, but the pressure ratio is increased. Although it can reach a high-temperature hot water of 65°C, the heating efficiency is low, resulting in high requirements for the material structure strength, thereby increasing the construction cost.

[0005] Regardless of whether it is a single-stage compression system or a bipolar compression system, a traditional condenser is usually used to achieve the high-temperature heat release function. The traditional condenser has a simple structure and uses a cooling medium to cool the high-temperature and high-pressure gaseous refrigerant. The fluid flow rate is generally 1m / s to 3m / s, and the heat release efficiency is low. Summary of the Invention

[0006] The present invention aims to provide a subcritical flow vortex heat exchanger with high heat release efficiency and a subcritical flow state of refrigerant gas, so as to solve the problems that it is difficult to obtain high-temperature heating capacity at a low pressure ratio using a single-stage compression system, resulting in limited application value and scope of low-temperature heat energy recovery, and the problem that the pressure ratio of a bipolar compression system increases, resulting in low heating efficiency and high requirements on material structure strength.

[0007] To this end, the technical solution adopted by the present invention is: a subcritical flow vortex heat exchanger, including an exchanger shell, an air inlet nozzle extending horizontally and connected to the top of the exchanger shell, a cold end gas outlet centered at the left end of the exchanger shell, and a hot end gas outlet centered at the right end of the exchanger shell. The exchanger shell is in the shape of a long tube as a whole, and a heat exchange core tube is coaxially installed in the middle right part of the cavity. The heat exchange core tube divides the inner cavity of the exchanger shell into an energy separation zone and a cooling water zone. The left cavity of the exchanger shell is connected to the air inlet nozzle and serves as a high-speed vortex for the high-pressure and high-temperature gas entering tangentially. In the gas vortex flow zone of the flow, when the gas spiraling into the energy separation zone is separated into an inner layer of low-temperature gas and an outer layer of high-temperature gas under the action of a high-speed centrifugal vortex, the gas in the outer layer of high-temperature gas in a subcritical flow state transfers heat with the cooling water zone with the help of a heat exchange core tube. The hot-end gas outlet is used to guide out the low-temperature and high-pressure gas-liquid mixture condensed after the heat transfer of the outer layer of high-temperature gas. The cold-end gas outlet is provided with a cold steam guide pipe extending axially from the outside of the left end of the exchanger shell to the energy separation zone. The cold steam guide pipe is used to guide out the low-temperature and low-pressure gas-liquid mixture condensed after the energy of the inner layer of low-temperature gas is exchanged with the outer layer of high-temperature gas.

[0008] As a preferred embodiment of the above scheme, the transition section of the gas vortex flow zone adjacent to the heat exchange core tube is provided with a tapered tube connected from the inner wall of the exchanger shell to the left end of the heat exchange core tube. The tapered tube is used to seal the left end of the cooling water zone and guide the axial rotation of the gas in the gas vortex flow zone to the energy separation zone, serving two purposes at one stroke. In addition, the inner diameter is contracted in the transition section, the gas is compressed, the pressure is increased, and the molecular vibration frequency is accelerated, thereby increasing the gas vortex speed and guiding the gas flow direction. The design is exquisite.

[0009] It is further preferred that the inner wall of the heat exchange core tube is spirally ringed with metal inner spiral fins and the outer wall is spirally ringed with metal outer spiral fins, so that the gas in the subcritical flow state in the outer layer of high-temperature gas can transfer heat to the cooling water area with the help of the metal inner spiral fins and the metal outer spiral fins, and the spiral density can be flexibly changed according to the actual heat transfer requirements. The design is reasonable, and heat is transferred through the inner and outer fins to ensure efficient heat transfer.

[0010] More preferably, the exchanger housing is radially provided with a cooling water inlet and a cooling water outlet at the left and right ends corresponding to the cooling water zone, and adopts cold water cooling, which has low cost and reasonable design.

[0011] It is further preferred that the metal inward-spiraling fins and the metal outward-spiraling fins are both made of porous metal. Compared with ordinary metal plates, under the same plate specifications, porous metal can greatly increase the contact heat exchange area of ​​gas molecules by nearly 20 times, and also extend the heat exchange process inside and outside the heat exchange core tube, greatly improving the heat exchange capacity. Porous metal is mainly used for vibration reduction and sound absorption, but the large specific surface area of ​​porous metal is rarely used. There is currently no precedent for its application to heat exchange equipment, and the material selection is clever.

[0012] It is further preferred that the outer ends of the metal outward-spiral fins are close to the inner wall of the exchanger shell, which increases the contact area between the cooling medium and the metal outward-spiral fins and improves the heat transfer effect. There is an axial and radial distance between the metal inward-spiral fins and the inner end of the cold steam guide tube, which effectively avoids the cold steam guide tube and the metal inward-spiral fins from colliding, causing mutual interference and affecting the heat transfer or cold air extraction effect. The layout is reasonable.

[0013] Further preferably, the hot end gas outlet diameter is located between the inner diameter of the heat exchange core tube and the cold end gas outlet diameter, and the design structure is reasonable to ensure that the low and high temperature stratified gases in the inner and outer layers flow out without confusion.

[0014] Further preferably, the right end of the cold steam guide tube is provided with a conical inward-shaped microporous plate, which can reduce the pressure of high-temperature and high-pressure gas molecules mixed with the inner layer of low-temperature gas, and the structure is reasonable.

[0015] Beneficial effects of the present invention:

[0016] (1) Compared with the single-stage compression system, which is difficult to obtain high-temperature heating capacity, resulting in limited application value and scope of low-temperature heat recovery, and the double-stage compression system, which has defects such as increased pressure ratio, low heating efficiency, and high requirements for material structure strength, this solution directly replaces the traditional condenser in the original equipment, thereby directly achieving high-temperature hot water of 80℃ to 90℃ in the single-stage compression system. Compared with the high-temperature hot water below 50℃ of the traditional condenser in the original single-stage compression system, the heating capacity is obviously stronger.

[0017] (2) High-pressure and high-temperature gas enters the gas vortex flow zone horizontally through the air inlet nozzle to form a high-speed vortex flow. After entering the energy separation zone, the gas molecules in the inner layer transfer kinetic energy to the gas molecules in the outer layer, causing the gas molecules in the inner layer to lose kinetic energy, reduce the vibration frequency, and reduce the temperature, while the gas molecules in the outer layer gain kinetic energy, increase the vibration frequency, and increase the temperature, thereby generating radial energy transfer and separation along the central axis of the energy separation zone. The inner layer is a low-temperature zone, and part of the gas condenses into a gas-liquid mixture and is discharged from the cold end gas outlet; while the outer layer is a high-temperature zone, and part of the gas rotating at high speed close to the critical temperature will present a subcritical flow state, and after transferring the heat to the cooling water in the cooling water zone through the heat exchange core tube, it is discharged from the hot end gas outlet; the structure is interconnected and the design is exquisite.

[0018] (3) The present invention is completely different from the existing condenser technology principle, structure and efficiency. It is a new type of thermal device designed and manufactured under the innovative technical concept. By generating a high temperature close to the critical point, the heat exchange temperature difference of the heat exchange core tube is increased, thereby increasing the heat transfer capacity, achieving the effects of low pressure ratio, high temperature hot water and high heating energy efficiency ratio, and greatly improving the overall benefit and value of low temperature heat energy recovery.

[0019] (4) The air inlet nozzle extends horizontally and connects to the top of the exchanger shell, thereby ensuring that high-temperature and high-pressure gas can enter horizontally at high speed. In the heat exchange core tube, the high-speed tangential wall flow will destroy the wall laminar flow that hinders heat transfer, making the airflow in a turbulent state, greatly improving the convective heat transfer coefficient between the airflow and the tube wall, and increasing the heat transfer capacity. Compared with the existing condenser, when transferring the same amount of heat, the device volume is greatly reduced and the heat transfer efficiency is high.

[0020] To sum up, it has the advantages of stronger heating capacity, low pressure ratio, high temperature hot water, high heating energy efficiency ratio and high heat transfer efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural cross-sectional view of the present invention.

[0022] Figure 2 for Figure 1 Right view of .

[0023] Figure 3 Schematic diagram of a single-stage compression system.

[0024] Figure 4 Schematic diagram of a two-stage compression system.

[0025] Figure 5 Schematic diagram of a heat recovery system that replaces the condenser with a subcritical flow vortex heat exchanger. DETAILED DESCRIPTION

[0026] The present invention will be further described below by way of examples and in conjunction with the accompanying drawings:

[0027] Combine Figure 1 — Figure 5 As shown, a subcritical flow vortex heat exchanger consists of an exchanger shell 1, an air inlet nozzle 2 extending horizontally and connected to the top of the exchanger shell 1, a cold end gas outlet 3 centered at the left end of the exchanger shell 1, and a hot end gas outlet 4 centered at the right end of the exchanger shell 1.

[0028] The heat exchanger shell 1 is in the shape of a long tube as a whole, and a heat exchange core tube 11 is coaxially installed in the right middle part of the cavity.

[0029] The heat exchange core tube 11 divides the inner cavity of the exchanger shell 1 into an energy separation zone 5 and a cooling water zone 6 .

[0030] A cooling water inlet 61 and a cooling water outlet 62 are radially provided at the left and right ends of the exchanger housing 1 corresponding to the cooling water area 6 .

[0031] The left cavity of the exchanger housing 1 is connected to the air inlet nozzle 2 and serves as a gas vortex flow zone 7 for the high-speed tangentially entering high-pressure and high-temperature gas to form a high-speed vortex flow.

[0032] A transition section of the gas vortex flow region 7 adjacent to the heat exchange core tube 11 is provided with a tapered tube 8 connected from the inner wall of the exchanger shell 1 to the left end of the heat exchange core tube 11 .

[0033] The reducer 8 is used to seal the left end of the cooling water zone 6 and guide the axial swirl flow of the gas in the gas vortex flow zone 7 to the energy separation zone 5 .

[0034] When the gas swirling into the energy separation zone 5 is separated into an inner layer of low-temperature gas and an outer layer of high-temperature gas under the action of a high-speed centrifugal vortex, the gas in the outer layer of high-temperature gas in a subcritical flow state transfers heat with the cooling water zone 6 with the help of the heat exchange core tube 11.

[0035] The inner wall of the heat exchange core tube 11 is spirally circumferentially provided with metal inner spiral fins 111, and the outer wall is spirally circumferentially provided with metal outer spiral fins 112, so that the gas in the subcritical flow state in the outer layer of high-temperature gas can transfer heat with the cooling water area 6 with the help of the metal inner spiral fins 111 and the metal outer spiral fins 112.

[0036] The metal inner spiral fins 111 and the metal outer spiral fins 112 are preferably made of porous metal.

[0037] The outer ends of the metal outward-turning fins 112 are close to the inner wall of the exchanger housing 1 .

[0038] There is a distance between the metal inwardly spiral fin 111 and the inner end of the cold steam guide pipe 31 in both the axial and radial directions.

[0039] The cold end gas outlet 3 is provided with a cold gas guide pipe 31 extending axially from the outside of the left end of the exchanger shell 1 to the energy separation zone 5 .

[0040] The cold steam guide pipe 31 is used to guide the low-temperature and low-pressure vapor-liquid mixed state formed by condensing the inner layer of low-temperature gas after exchanging energy with the outer layer of high-temperature gas.

[0041] A conical microporous plate is provided at the right end of the cold steam guide pipe 31 .

[0042] The hot end gas outlet 4 is used to discharge the low-temperature and high-pressure gas-liquid mixture that is condensed after the heat transfer of the outer high-temperature gas.

[0043] The diameter of the hot end gas outlet 4 is between the inner diameter of the heat exchange core tube 11 and the diameter of the cold end gas outlet 3.

[0044] A subcritical flow vortex heat exchange heat energy recovery method, the specific implementation steps are as follows:

[0045] Step S1: The refrigerant gas is subjected to heat absorption at a low temperature by the evaporator A so that the refrigerant gas is in a low-temperature and low-pressure gas state, and the low-temperature and low-pressure gas is transferred into the compressor B to form a high-temperature and high-pressure gas.

[0046] The low-temperature heat source evaporator A adopts a conventional horizontal shell and tube liquid-liquid heat exchanger, which has a low-temperature heat source water inlet / outlet and a refrigerant inlet / outlet. The refrigerant inlet is connected to the outlet of the thermal expansion valve D, and the refrigerant outlet is connected to the inlet of the low-pressure ratio compressor B. On both sides of the tube inside the low-temperature heat source evaporator A, low-temperature heat source water that provides heat energy flows outside the tube, and refrigerant that absorbs heat energy flows inside the tube. The low-temperature heat source water transfers heat energy to the refrigerant through the tube wall. After the refrigerant absorbs heat energy from the low-temperature heat source water, its physical state sublimates from low-pressure liquid to low-temperature and low-pressure gas.

[0047] The low-temperature and low-pressure vapor of the refrigerant is sucked into the low-pressure ratio compressor B. After being compressed by the compressor, the physical state of the refrigerant changes to a high-temperature and high-pressure vapor relative to that before compression; the high-temperature and high-pressure vapor of the refrigerant is sprayed into the subcritical flow vortex heat exchanger connected thereto.

[0048] Step S2: The high-temperature and high-pressure gas is discharged into the subcritical flow vortex heat exchanger, and then the high-temperature and high-pressure gas is released at a high temperature position with the help of the subcritical flow vortex heat exchanger. The high-temperature and high-pressure gas enters the inner cavity of the subcritical flow vortex heat exchanger at a high speed tangentially to form a high-speed vortex flow, and radial energy transfer and separation are generated under the action of the high-speed centrifugal vortex. The energy of the inner layer gas will be transferred to the outer layer gas, thereby forming an inner layer of low-temperature and low-pressure gas and an outer layer of high-temperature and high-pressure gas.

[0049] Step S3, the low-temperature and low-pressure vapor-liquid mixture after the low-temperature and low-pressure gas is condensed is discharged from the cold-end vapor outlet 3 of the subcritical flow vortex heat exchanger to the economizer E. Part of the gas in the high-temperature and high-pressure gas is close to the critical temperature due to high-speed rotation, thus presenting a subcritical flow state, and heat is transferred in the inner cavity of the subcritical flow vortex heat exchanger. Then, the low-temperature and high-pressure vapor-liquid mixture after heat transfer is discharged from the hot-end vapor outlet 4 of the subcritical flow vortex heat exchanger to the expansion valve D for separate decompression, and the formed low-temperature and low-pressure vapor-liquid mixture is then discharged into the economizer E.

[0050] In step S4, the low-temperature and low-pressure vapor-liquid mixture discharged into the economizer E is transferred to the next expansion valve D for collective decompression, and finally discharged back to the evaporator A. Steps S1-S4 are repeated to perform a new round of heating cycle.

[0051] The refrigerant is preferably Freon R-22, which has a critical pressure of 4.99 MPA. Conventional compression must be compressed to 4.99 MPA to reach the critical temperature, while this method only requires 1 MPA to reach the critical temperature of Freon R-22, greatly reducing energy consumption.

Claims

1. A subcritical flow vortex heat exchanger, characterized in that: The invention comprises an exchanger shell (1), an air inlet nozzle (2) extending horizontally and connected to the top of the exchanger shell (1), a cold end gas outlet (3) centrally located at the left end of the exchanger shell (1), and a hot end gas outlet (4) centrally located at the right end of the exchanger shell (1). The exchanger shell (1) is in the shape of a long tube as a whole, and a heat exchange core tube (11) is coaxially installed in the middle right part of the cavity. The heat exchange core tube (11) divides the inner cavity of the exchanger shell (1) into an energy separation zone (5) and a cooling water zone (6). The left cavity of the exchanger shell (1) is connected to the air inlet nozzle (2) and serves as a gas vortex flow zone (7) for high-speed tangential high-pressure and high-temperature gas to form a high-speed vortex flow. When the gas swirls into the energy separation zone (5), it is separated into an inner layer of low-temperature gas and a cooling water zone (6) under the action of the high-speed centrifugal vortex. When the heat exchanger shell (1) is heated to 100 ℃ and the heat exchanger shell (2) is heated to 100 ℃, the heat exchanger shell (1) is heated to 100 ℃ and the heat exchanger shell (2) is cooled to 200 ℃ and the heat exchanger shell (3) is cooled to 200 ℃ and the heat exchanger shell (4) is cooled to 200 ℃ and the heat exchanger shell (3) is cooled to 200 ℃ and the heat exchanger shell (1) is cooled to 200 ℃ and the heat exchanger shell (2) is cooled to 200 ℃ and the heat exchanger shell (3) is cooled to 200 ℃ and the heat exchanger shell (3) is cooled to 200 ℃ and the heat exchanger shell (1 ...

2. The subcritical flow vortex heat exchanger according to claim 1, characterized in that: The transition section of the gas vortex flow zone (7) adjacent to the heat exchange core tube (11) is provided with a tapered tube (8) connected from the inner wall of the exchanger shell (1) to the left end of the heat exchange core tube (11), and the tapered tube (8) is used to seal the left end of the cooling water zone (6) and guide the axial rotation of the gas in the gas vortex flow zone (7) to the energy separation zone (5).

3. The subcritical flow vortex heat exchanger according to claim 1, characterized in that: The heat exchange core tube (11) is provided with metal inner spiral fins (111) on the inner wall in a spiral manner, and metal outer spiral fins (112) on the outer wall in a spiral manner, so that the gas in a subcritical flow state in the outer layer of high-temperature gas can transfer heat with the cooling water area (6) by means of the metal inner spiral fins (111) and the metal outer spiral fins (112).

4. The subcritical flow vortex heat exchanger according to claim 3, characterized in that: The metal inner-rotating ribs (111) and the metal outer-rotating ribs (112) are both made of porous metal.

5. The subcritical flow vortex heat exchanger according to claim 3, characterized in that: The outer end of the metal outward-turning fin (112) is close to the inner wall of the exchanger shell (1), and the metal inward-turning fin (111) is spaced apart from the inner end of the cold steam guide tube (31) in both the axial and radial directions.

6. The subcritical flow vortex heat exchanger according to claim 1, characterized in that: The hot end gas outlet (4) has a diameter between the inner diameter of the heat exchange core tube (11) and the diameter of the cold end gas outlet (3).

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