Atomizing diverter

Abstract

The present invention discloses an atomizing diverter, which can actively adjust the flow pattern of the incoming flow into a mist flow and solve the problem of downstream pressure wave transmission to the upstream, so as to adapt to more scenarios. It includes an atomizing section, an atomizing particle diffusion section and a diverter section connected in sequence. The atomizing section includes a number of atomizing flow channels for forming a mist flow, and each atomizing flow channel is composed of an equal-diameter atomizing flow channel, a tapered section atomizing flow channel and a throat atomizing flow channel arranged in sequence. The atomizing particle diffusion section is composed of an atomizing particle expanding section and an atomizing particle contracting section. The diverter section includes a number of critical diverter flow channels for forming a high-speed critical flow, and each critical diverter flow channel is composed of an equal-diameter critical flow channel, a tapered section critical flow channel, a throat critical flow channel and a tapered section critical flow channel arranged in sequence. The diverter can make the gas-liquid two-phase refrigerant form a stable mist flow, and then pass through the diverter section to achieve uniform liquid supply, thereby improving the heat exchange performance of the evaporator and the performance of the refrigeration system.

Description

Technical Field

[0001] The present invention relates to a regulating system, and more particularly to an atomizing flow splitter based on mist flow formation and applied in the regulating system. Background Art

[0002] The evaporator in a refrigeration system faces the challenge of evenly distributing the throttled gas-liquid two-phase refrigerant upstream to multiple downstream evaporation branches. During the diversion process, the gas-liquid flow rate and dryness of each downstream branch are not completely consistent due to the unstable flow state of the upstream refrigerant gas-liquid two-phase flow. This phenomenon, known as phase separation, occurs. In some branches, too little liquid refrigerant is distributed, causing rapid evaporation and premature entry into the superheat zone. The insufficient utilization of the heat transfer area in the superheat zone leads to reduced cooling capacity and a significant deterioration in the overall performance of the refrigeration system. Meanwhile, an oversupply of liquid refrigerant in other branches often results in unevaporated droplets at the evaporator outlet, causing the compressor to carry liquid with it, damaging its operation.

[0003] Compared with single-phase flow, the interaction mechanism of gas-liquid two-phase flow is complex and is affected by many factors, including diverter structure, upstream fluid flow state, downstream pressure wave oscillation, etc.

[0004] The patent application number is 2019104584601, and the invention name is "Atomizing nozzle type splitter and refrigeration system". The patent document discloses an atomizing nozzle type splitter, which uses a gas-liquid two-phase flow fluid to form diffused atomized particles after flowing through the atomizing nozzle. The atomized particles are rectified by the rectifier into an ideal mist flow. After that, the ideal mist flow enters the sonic nozzle to form a two-phase critical flow. The two-phase critical flow reaches the critical flow velocity of the two-phase flow, so that the downstream unstable pressure wave cannot be transmitted to the upstream pipeline, thereby improving the distribution effect of the two-phase flow refrigerant. However, since the atomizing nozzle is located in the middle of the liquid supply pipe, the atomized particles formed after the two-phase refrigerant passes through the atomizing nozzle diffuse in a space with a constant pipe diameter. This will cause the collision between the atomized particles to intensify, and accumulate into an uneven liquid film in advance, which will lead to unbalanced distribution before diversion. At the same time, due to the perpendicular arrangement of the sonic nozzle and the incoming flow direction, the atomized flow will impact the wall of the distribution chamber and accumulate into a liquid film instead of directly entering the critical nozzle, resulting in intensified collisions of atomized particles in the distribution chamber and oscillation of the liquid film, which is not conducive to the uniform distribution of the two-phase refrigerant. On the other hand, the diverter tube is arranged perpendicular to the incoming flow direction, which increases the resistance of the refrigerant entering the diverter tube, reduces the refrigerant flow rate, and reduces the distribution performance. In addition, there are also problems such as the complex structure of the critical diverter section and the difficulty of processing. Therefore, it is necessary to design a new type of atomizing diverter to actively adjust the incoming two-phase refrigerant flow pattern to a mist flow, so that the two-phase flow refrigerant can achieve a better distribution effect and adapt to the refrigerant distribution in more scenarios. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problem that traditional diverters cannot actively adjust the flow pattern of the incoming flow, cannot solve the problem of poor diversion performance caused by the transmission of downstream pressure waves to upstream pipelines, and the problem that the atomized particles in the existing atomizing nozzle diverter collide severely and easily accumulate into uneven liquid films, resulting in poor distribution effect. An atomizing diverter based on mist flow formation and critical diversion is provided, which can better actively adjust the flow pattern of the incoming flow to adapt to the uniform distribution of refrigerant in more scenarios.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] An atomizing flow splitter comprises an atomizing section, an atomizing particle diffusion section and a critical flow splitting section connected in sequence; the atomizing section comprises a plurality of atomizing flow channels for forming a mist flow, each of the atomizing flow channels is composed of a coaxial equal-diameter atomizing flow channel, a tapered section atomizing flow channel and a throat atomizing flow channel arranged in sequence; the axis of each atomizing flow channel is parallel to the incoming flow direction; the atomizing particle diffusion section is composed of an atomizing particle gradually expanding section and an atomizing particle gradually contracting section; the critical flow splitting section comprises a plurality of critical flow splitting flow channels for forming a critical flow, each of the critical flow splitting flow channels is composed of a coaxial equal-diameter critical flow channel, a tapered section critical flow channel, a throat critical flow channel and a gradually expanding section critical flow channel arranged in sequence; the inlet of the equal-diameter atomizing flow channel is connected to the inlet liquid supply pipe, and the outlet of the throat atomizing flow channel is connected to the atomizing The inlet end of the particle expanding section is connected, and the outlet end of the atomized particle converging section is connected to the inlet end of the equal-diameter critical flow channel; the cross-section of any position of several of the critical diversion flow channels is circular, and several of the critical diversion flow channels are arranged in a plane circle along the outlet cross-section of the atomized particle converging section, and are arranged in parallel with the atomizing flow channel; the incoming two-phase refrigerant passes through the multiple atomizing flow channels evenly distributed in the atomizing section, and the flow type is adjusted to a diffuse mist flow, and the high-speed atomized particles are completely diffused in the atomized particle expanding section, and the diffused uniform mist flow is then gathered at the inlet of the critical diversion flow channel through the atomized particle converging section; the throat critical flow channel of the critical diversion flow channel causes the mist gas-liquid two-phase flow refrigerant to form a critical two-phase flow, cutting off the transmission of the unstable pressure wave of the downstream branch to the upstream.

[0008] In the atomizing section, the cross-section of the atomizing flow channel at any position is circular, and several of the atomizing flow channels are evenly arranged on the same circumference and center of a circle with the center line of the atomizing section as the center, and are arranged parallel to the incoming flow direction; the inlet circles of the equal-diameter atomizing flow channels are evenly distributed on the inlet cross-section of the atomizing section.

[0009] The atomized particle gradually expanding section and the atomized particle gradually contracting section are both hollow tube structures, and the flow channel cross-sectional profiles of the atomized particle gradually expanding section and the atomized particle gradually contracting section are both straight lines; the angle between the flow channel cross-sectional profile of the atomized particle gradually expanding section and the center line of the atomized flow channel is αThe angle between the cross-sectional profile of the atomized particle tapering section and the center line of the critical diversion channel is 15-30°. β 15-30°.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The diverter of the present invention includes an atomizing section, an atomizing particle diffusion section and a diverting section connected in sequence, based on the formation of mist flow and critical diversion, wherein the atomizing particle diffusion section is composed of an atomizing particle gradually expanding section and an atomizing particle gradually contracting section. The high-speed diffusion of atomized particles in the atomizing particle gradually expanding section can avoid the intensification of collisions between atomized particles, and avoid the premature accumulation of large liquid films in the atomizing chamber that affect the mist flow formation effect. The structure of the atomizing particle gradually expanding section and the atomizing particle gradually contracting section is also conducive to the liquid film accumulated by the refrigerant in the distribution stage to flow back along the wall of the gradually expanding section and the gradually contracting section, avoiding obstruction of the mist flow to the outlet to participate in the distribution. Since the atomizing section is composed of a number of atomizing flow channels, it is conducive to adjusting the incoming flow type, ensuring the distribution balance before diversion, and being able to adapt to the uniform distribution of refrigerant in more scenarios, thereby helping to improve the reliability of the system operation and ensuring the refrigeration performance of the refrigeration system.

[0012] 2. In the diverter of the present invention, the diverter section is composed of several critical diverter flow channels, each of which is composed of an equal-diameter critical flow channel, a tapering section critical flow channel, a throat critical flow channel and a gradually expanding section critical flow channel, and is arranged in parallel with the atomizing flow channel. The formed mist flow can directly reach the inlet of the critical flow channel, reducing the flow resistance, avoiding the mist flow from first colliding with the top of the cavity and accumulating into a liquid film before participating in the distribution, and can distribute the two-phase refrigerant more evenly at the outlet of each branch. The throat critical flow channel of the critical diverter flow channel causes the mist gas-liquid two-phase flow refrigerant to form a critical two-phase flow, cutting off the transmission of the unstable pressure wave of the downstream branch to the upstream.

[0013] 3. In the diverter of the present invention, the structure of the critical diverter section has been simplified, which reduces the difficulty and cost of processing and improves the feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Shown is an overall schematic diagram of the atomizing splitter of the present invention;

[0015] Figure 2 Shown Figure 1 The main view;

[0016] Figure 3 Shown Figure 1 Left view of;

[0017] Figure 4 Shown Figure 3 AA section view;

[0018] Figure 5 Shown are several atomization flow channel layout diagrams;

[0019] Figure 6 Shown are the layout diagrams of several critical diversion flow channels;

[0020] Figure 7 The figure shows the structure of the atomizing splitter according to the embodiment of the present application;

[0021] Figure 8 Shown is a schematic diagram of the structure of the sample Venturi splitter;

[0022] Figure 9 Shown is a simplified schematic diagram of the flow field structure of the sample atomization splitter;

[0023] Figure 10 Shown are the experimental data of superheat non-uniformity under different working conditions;

[0024] Figure 11 Shown are the experimental data of refrigerants under different working conditions;

[0025] Figure 12 Shown are experimental data of heat transfer coefficient under different working conditions;

[0026] Figure 13 Shown are the experimental data of evaporator pressure drop under different working conditions;

[0027] Figure 14 Shown are the experimental data of pressure drop in the diverter under different working conditions;

[0028] Figure 15 Shown is the experimental data of the pressure change at the outlet of the sample Venturi splitter;

[0029] Figure 16 The figure shows the experimental data of the outlet pressure change of the atomizing splitter in the embodiment of the present application;

[0030] Figure 17 Shown is the simulated phase distribution cloud diagram of the sample atomization splitter;

[0031] Figure 18 Shown is a simulated phase distribution cloud diagram of the atomizing splitter according to an embodiment of the present application;

[0032] Figure 19 Shown are two types of flow splitters simulating mass flow non-uniformity under different inlet conditions.

[0033] In the figure: 1. Inlet liquid supply pipe; 2. Atomizing flow channel; 2-1. Equal-diameter atomizing flow channel; 2-2. Gradual-converging section atomizing flow channel; 2-3. Throat atomizing flow channel; 3. Gradual-expanding section of atomized particles; 4. Gradual-converging section of atomized particles; 5. Critical diversion flow channel; 5-1. Equal-diameter critical flow channel; 5-2. Gradual-converging section critical flow channel; 5-3. Throat critical flow channel; 5-4. Gradual-expanding section critical flow channel. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] The schematic diagram of the atomizing splitter of the present invention is as follows Figures 1-6 As shown, it includes an atomizing section, an atomizing particle diffusion section and a critical diversion section connected in sequence. The atomizing section includes a plurality of atomizing flow channels 2 for forming a mist flow, and each of the atomizing flow channels 2 is composed of a coaxial equal-diameter atomizing flow channel 2-1, a tapering section atomizing flow channel 2-2 and a throat atomizing flow channel 2-3 arranged in sequence, and the axis of each atomizing flow channel is parallel to the incoming flow direction. The atomizing particle diffusion section is composed of an atomizing particle expanding section 3 and an atomizing particle contracting section 4. The critical diversion section includes a plurality of critical diversion flow channels 5 for forming a critical flow, and each of the critical diversion flow channels 5 is composed of a coaxial equal-diameter critical flow channel 5-1, a tapering section critical flow channel 5-2, a throat critical flow channel 5-3 and a gradually expanding section critical flow channel 5-4 arranged in sequence. The inlet of the equal-diameter atomizing flow channel 2-1 is connected to the inlet liquid supply pipe 1, the outlet of the throat atomizing flow channel 2-3 is connected to the inlet end of the atomizing particle gradually expanding section 3, and the outlet end of the atomizing particle gradually converging section 4 is connected to the inlet end of the equal-diameter critical flow channel 5-1.

[0036] In the atomizing section, the cross section of any position of the atomizing flow channel 2 is circular. Figure 5 As shown, preferably, the plurality of atomizing channels 2 are evenly arranged on the same circumference and at the center of a circle with the center line of the atomizing section as the center, and are arranged parallel to the incoming flow direction. The inlet circles of the equal-diameter atomizing channels 2-1 are evenly distributed on the inlet cross-section of the atomizing section, with the goal of ensuring that the incoming refrigerant flows evenly through each atomizing channel 2 as much as possible. The use of multiple atomizing channels in the atomizing section is conducive to ensuring uniform atomization of the incoming refrigerant two-phase fluid. The throat length and throat aperture of the throat atomizing channel 2-3 require that the refrigerant can form a mist flow.

[0037] The atomized particle expanding section 3 and the atomized particle converging section 4 are both hollow tubular structures, and the cross-sectional profiles of the flow paths of the atomized particle expanding section 3 and the atomized particle converging section 4 are both straight lines. After leaving the atomizing section, the refrigerant enters the atomized particle expanding section 3 in the atomized particle diffusion section and passes through the atomized particle converging section 4 until it reaches the outlet of the atomized particle diffusion section. The structure of the atomized particle expanding section 3 and the atomized particle converging section 4 also facilitates the backflow of the liquid film formed by the accumulation of refrigerant during the distribution phase along the walls of the expanding and converging sections, thereby avoiding obstruction of the mist flow toward the outlet.

[0038] like Figure 2 The function of the atomized particle expansion section 3 is to allow the mist flow formed by the atomized flow channel 2 to spread to the entire cavity, forming a uniform distribution effect. The angle between the atomized particle expansion section profile and the center line of the atomized flow channel 2 is recorded as α The diffusion angle of the outgoing fluid is affected by the mass flow rate of the refrigerant and the diameter of the throat atomizing channel 2-3. The angle between the center line of the atomizing channel 2 and the atomized particle expansion section 3 is α Generally 15-30°.

[0039] like Figure 2 The mist refrigerant in the atomized particle gradually expanding section 3 diffuses to the atomized particle gradually contracting section 4. The angle between the profile of the atomized particle gradually contracting section 4 and the center line of the critical diversion channel 5 is recorded as β The mist flow refrigerant in the atomized particle gradually expanding section 3 is gathered at the entrance of the critical diversion channel 5 through the atomized particle gradually contracting section 4, which is beneficial to the distribution of the refrigerant. β Generally 15-30°.

[0040] Several critical diversion channels are arranged as follows Figure 6 As shown, preferably, the cross-section of any position of the critical diversion flow channels 5 is circular. The critical diversion flow channels are arranged in a plane circle along the outlet cross-section of the atomized particle tapering section and are arranged parallel to the atomizing flow channel, so that the fully diffused mist flow directly enters the critical diversion flow channel, avoiding the mist flow first hitting the top of the cavity and accumulating into a liquid film before participating in distribution, so that the two-phase refrigerant is distributed more evenly.

[0041] The incoming two-phase refrigerant passes through multiple atomizing flow channels evenly distributed in the atomizing section, and the flow type is adjusted to a diffuse mist flow. The high-speed atomized particles are completely diffused in the atomizing particle expansion section, which can avoid the intensification of collisions between the atomized particles and the premature accumulation of large liquid films in the atomizing chamber that affect the mist flow formation effect. The diffused and formed uniform mist flow is then gathered at the entrance of the critical diversion flow channel through the atomizing particle contraction section; the structure of the atomizing particle expansion section and the atomizing particle contraction section is also conducive to the liquid film accumulated by the refrigerant in the distribution stage to flow back along the wall of the expansion section and the contraction section, avoiding obstruction of the mist flow to the outlet.

[0042] The structure of the critical diversion section has been simplified, reducing processing difficulty and cost. This allows the fully diffused mist flow to enter the critical diversion channel directly, preventing the mist flow from first impacting the top of the cavity and accumulating into a liquid film before participating in distribution. This allows the two-phase refrigerant to be distributed more evenly, reducing flow resistance and distributing the two-phase refrigerant more evenly to each branch outlet. The critical flow channel at the throat of the critical diversion channel allows the mist gas-liquid two-phase flow refrigerant to form a critical two-phase flow, cutting off the transmission of unstable pressure waves from the downstream branch to the upstream.

[0043] During use, the inlet liquid supply pipe 1 is connected to the pipeline after the expansion valve of the refrigeration system by brazing, and the outlet of the critical flow channel 5-4 of the gradually expanding section is connected to several thin tubes by brazing, and the thin tubes are connected to the inlet pipes of each branch of the evaporator of the refrigeration system by brazing. After being throttled by the expansion valve of the refrigeration system, the gas-liquid two-phase refrigerant flows into the inlet liquid supply pipe 1, enters the tapered section atomizing flow channel 2-2 through several equal-diameter atomizing flow channels 2-1, is accelerated into the throat atomizing flow channel 2-3, diffuses to form a mist flow, and then enters the atomized particle gradually expanding section 3 in the atomizing particle diffusion section to diffuse and flow, and then passes through the atomized particle gradually shrinking section 4 to make the mist flow refrigerant gather to form a two-phase flow refrigerant distribution with high wall density and low middle density, and enters the equal-diameter critical flow channel 5-1, and then the mist flow gas-liquid two-phase refrigerant inside the equal-diameter critical flow channel 5-1 is accelerated through the tapered section critical flow channel 5-2, and forms a two-phase critical flow refrigerant in the throat critical flow channel 5-3, and then is ejected into the evaporator of the refrigeration system through the gradually expanding section critical flow channel 5-4 at a critical flow velocity. The atomizing flow divider of the present invention can adjust the flow pattern and evenly distribute the incoming flow, and solve the problem of downstream pressure wave transmission to the upstream through the critical action of two-phase flow. The gas-liquid two-phase refrigerant after expansion throttling can be evenly distributed to each branch of the evaporator for efficient evaporation. Example

[0044] In this embodiment, an atomizing diverter model of the present application is established for experimental and simulation verification.

[0045] The structural parameters of the atomizing splitter model established in this embodiment are shown in the attached Figure 7 As shown, α 19° ，β It is 21°.

[0046] In order to verify the superior performance of the atomizing diverter of this embodiment compared with the traditional diverter, and to verify the inhibitory effect of the critical flow channel on the downstream pressure wave oscillation, a model of a sample Venturi diverter was established for experimental comparative analysis. In order to analyze and verify the superiority of the atomizing diverter structure of this application compared with the atomizing diverter structure of the patent application No. 2019104584601, a simplified flow domain model of the sample atomizing diverter mentioned in the patent application No. 2019104584601 was established for simulation comparative analysis. The structural parameters of the atomizing nozzle and sonic nozzle of the sample atomizing diverter as well as the overall diameter and length are similar to those of the atomizing diverter of the embodiment. The structural parameters of the established sample Venturi diverter model are shown in the attached figure. Figure 8 As shown in the attached figure, the simplified model structure parameters of the sample atomizer splitter are as follows: Figure 9 shown.

[0047] Experimental methods:

[0048] The experiments were conducted on a dry evaporator performance test bench. The temperature of the constant-temperature chamber was maintained at 0°C. The test chamber was operated at -24°C, -22°C, -20°C, -18°C, and -16°C. Under each test temperature condition, the evaporator evaporation temperature was maintained at 10°C below the test chamber ambient temperature, and the condensation temperature was controlled at 10°C above the outdoor ambient temperature. Three types of splitters were installed in the dry evaporator performance test bench. The superheat at the evaporator outlet was kept constant at 2°C to 4°C under each test condition. Parameters collected during the experiments included evaporator cooling capacity, heat transfer coefficient, pressure drop, and splitter superheat nonuniformity.

[0049] The cooling capacity is processed by taking the average value of the sum of the refrigerant side enthalpy difference method and the air side heat balance method.

[0050] Superheat non-uniformity is an important indicator for evaluating the performance of a flow divider. The smaller the overall superheat non-uniformity, the better the flow diversion effect of the flow divider and the more uniform the flow diversion.

[0051] The non-uniformity of superheat is obtained by the following formula:

[0052] ;

[0053] Where, is the unevenness of the overall superheat of the diverter, n is the number of branch pipes of the finned evaporator, is the outlet superheat of each branch pipeline, It is the average value of the superheat at the outlet of each branch pipeline.

[0054] Experimental results:

[0055] As attached Figure 10As shown, in the system operating conditions, the superheat unevenness of the two diverters does not change much with the change of evaporation temperature. The sample Venturi diverter cannot adjust the flow pattern of the upstream flow due to its structural limitations, and it is also unable to respond to the downstream pressure wave oscillation. This results in the superheat unevenness of the sample Venturi diverter being always higher than that of the atomizing diverter of this embodiment. On the premise that the critical diverter channel solves the influence of the pressure wave, the atomizing diverter of this embodiment changes the upstream refrigerant flow pattern by constructing a mist flow, thereby achieving uniform distribution. From the calculation of superheat unevenness, it can be obtained that the atomizing diverter of this embodiment has a sufficiently excellent uniform distribution ability. The superheat unevenness of the atomizing diverter of this embodiment is 20.8% lower than that of the sample Venturi diverter on average.

[0056] As attached Figure 11 、 Figure 12 As shown, the experimental results show that the cooling capacity and heat transfer coefficient of the dry evaporator refrigeration system using the two types of diverters both decrease as the evaporation temperature decreases, which is consistent with the traditional experimental results. The cooling capacity and heat transfer efficiency of the atomizing diverter of this embodiment gradually increase with the decrease of evaporation temperature, and the difference with the sample Venturi diverter. At -24°C, the cooling capacity of the atomizing diverter of this embodiment is 28% higher than that of the sample Venturi diverter. At the same time, the heat transfer coefficient of the atomizing diverter of this embodiment is 24.1% higher than that of the sample Venturi diverter. The results show that the atomizing diverter of this embodiment can better adapt to low temperature conditions. Overall, the cooling capacity of the atomizing diverter of this embodiment is on average 19.8% higher than that of the sample Venturi diverter, and the heat transfer coefficient of the atomizing diverter of this embodiment is on average 28.6% higher than that of the sample Venturi diverter. It can be seen that by constructing a mist flow combined with the critical diversion principle, the operating efficiency of the dry evaporator refrigeration system can be greatly improved, proving that the diverter of the patented structure has obvious advantages over the traditional diverter.

[0057] As attached Figure 13 、 14 As shown, the pressure sensor indicates that the two types of flow splitters do not significantly affect the evaporator pressure drop. Specifically, the atomizing flow splitter of this embodiment, due to its combined use of the atomizing flow channel and the critical flow splitting flow channel, results in a significant pressure drop within the splitter, exceeding 0.6 MPa. This effectively establishes a pressure gradient in the splitter's branch path, while maintaining a significant impact on the system's evaporator pressure drop. This demonstrates that the atomizing flow splitter of this embodiment largely fulfills the throttling function of a throttle valve.

[0058] As attached Figure 15 、 16As shown, when recording and studying the pressure drop at the outlet of each branch of different diverters, it was found that during the operation of the sample Venturi diverter in the system, the outlet pressure of each branch fluctuated significantly over time, was greatly affected by the downstream pressure wave oscillation, and could not maintain stable pressure operation for a long time. However, because the atomizing diverter of this embodiment uses a critical diversion channel to achieve critical flow and thus mitigate the impact of downstream pressure wave oscillations, the pressure change at the outlet of each branch during its operation is extremely small, and it can maintain stable pressure operation for a long time. This shows that the outlet critical flow structure of the atomizing diverter of this embodiment can effectively eliminate the influence of downstream pressure wave oscillations on diversion performance.

[0059] Simulation method:

[0060] CFD numerical simulations were performed using ANSYS Fluent 2023 R1 software, including the following key assumptions:

[0061] Consider heat transfer, phase change, and gas compressibility between two-phase flows;

[0062] The inlet pressure drop is negligible compared to the flow change caused by the diverter;

[0063] The direction of the gravity vector is opposite to the direction of the two-phase inflow.

[0064] To improve physical accuracy, a two-phase modeling strategy was adopted: the liquid phase was treated as an incompressible fluid, and temperature-dependent thermophysical properties (including density, dynamic viscosity, specific heat capacity, and thermal conductivity) were extracted from the REFPROP9.1 database for R22 refrigerant. Conversely, the gas phase was modeled as a compressible real fluid using the ideal gas model integrated into the CFD platform. Phase change dynamics and interphase heat transfer throughout the computational domain were specifically considered. The VOF model was used as the multiphase flow model, and the SST k-ω model was used as the turbulence model for the CFD simulations. The simulated installation angle was vertical.

[0065] Five sets of experimental data were selected for the inlet boundary condition. Mass flow rate was used as the inlet boundary condition. The gauge pressure at the splitter inlet and each branch outlet was experimentally collected. The pressure boundary conditions are shown in Table 1. Considering that the splitter was wrapped with a layer of insulation cotton during the experiment, an idealized assumption was made that there was no heat transfer and no slip on the wall, and that the wall temperature was consistent with the evaporation temperature.

[0066] Table 1 Simulation inlet boundary conditions

[0067]

[0068] Simulation results:

[0069] The cloud diagram of the sample atomizer splitter mentioned in patent application number 2019104584601 is shown in the attached figure. Figure 17As shown, the sample atomizer splitter can atomize two-phase refrigerant into dispersed particles and spray them toward the top of the splitter. However, due to the cylindrical cavity structure and narrow lateral space, the mist flow cannot fully diffuse, colliding with the walls and accumulating to form a liquid film. Furthermore, the inward protrusion of the rectifier prevents some of the mist flow from flowing directly toward the top, instead causing the mist flow to collide with the rectifier and accumulate into a liquid film. The rectifier also constricts the upward flow space for the mist flow, making it more likely for the upward-flowing mist flow to collide with the downward-flowing liquid film, increasing the resistance to the mist flow and leading to uneven distribution of the refrigerant phases entering the splitter chamber. Because the outlet critical channel of the splitter chamber is perpendicular to the refrigerant flow direction, the mist flow that successfully enters the splitter chamber collides with the top wall and accumulates to form a liquid film. The formed liquid film enters the splitter chamber and participates in lateral distribution. However, the phase distribution of the refrigerant two-phase flow entering the splitter chamber is uneven, and the two-phase flow entering the critical channel at the same time is significantly uneven. Taking all these effects into consideration, the structure of the atomizer diverter with patent application number 2019104584601 is not conducive to the full diffusion of the formed mist flow and the direct participation of the mist flow in the distribution, and the distribution uniformity is not good.

[0070] The cloud diagram of the atomizing splitter in this embodiment is shown in the attached figure. Figure 18 As shown in the figure, the splitter can atomize the two-phase refrigerant into dispersed particles and spray them toward the top of the splitter. α Angle with the tapered section β , α is 19°, β The angle of 21° makes the cavity space of the atomizing diverter of this embodiment larger, which is conducive to the full diffusion of the formed mist flow. The mist flow is not hindered by the diverter structure in the flow direction. At the same time, the outlet direction of the critical diverter channel is consistent with the incoming flow direction. The mist flow can flow directly and evenly to each critical diverter channel to participate in the distribution. Although the mist flow will still collide with the wall at the top of the diverter and accumulate into a liquid film, the overall phase distribution at the top of the diverter is very uniform. In addition, the liquid film accumulated at the top of the diverter can flow downward along the wall of the atomizing particle expansion section and the tapered section, and will not hinder the upward flow of the mist flow in the middle. Therefore, the angle of the atomizing particle expansion section is α Angle with the tapered section β The configuration plays an important role in the full diffusion and uniform distribution of the mist flow of the atomizing splitter of the present application. Taking these effects into consideration, it is shown that the structure of the atomizing splitter of the present embodiment is conducive to the full diffusion of the mist flow formed and the direct participation of the mist flow in the distribution, which has better distribution uniformity.

[0071] The mass flow non-uniformity can be calculated by the following formula:

[0072] ;

[0073] Where, is the unevenness of the total mass flow rate at the splitter outlet, is the number of branch pipes of the finned evaporator, is the total mass flow rate at the outlet of each branch pipeline, It is the average value of the total mass flow rate at the outlet of each branch pipeline.

[0074] As attached Figure 19 As shown, under different simulated inlet conditions, the simulation results of the mass flow non-uniformity STDm of the atomizing diverter of this embodiment are similar to the superheat non-uniformity variation range of its experimental results, and are lower than the STDm simulation value of the sample atomizing diverter, which is 27.7% lower on average, proving that the diversion uniformity of the sample atomizing diverter is much lower than that of the atomizing diverter of this embodiment, and the atomizing diverter structure of this embodiment is better than the atomizing diverter structure of patent application number 2019104584601.

[0075] The atomizing diverter of the present application can adjust the flow pattern of the incoming gas-liquid two-phase refrigerant to a mist flow for uniform distribution, and solve the problem of poor distribution effect caused by the pressure wave downstream of the refrigeration system diverter being transmitted upstream. It can adapt to a variety of scenarios, has a uniform distribution effect, can avoid damage caused by liquid carried by the compressor suction, and the decline in refrigeration performance caused by the rapid evaporation of liquid refrigerant entering the overheating zone in advance, thereby improving the reliability of system operation and helping to ensure the refrigeration performance of the refrigeration system.

[0076] The features of the various embodiments shown in the drawings of this application or mentioned in this specification are not necessarily to be understood as independent embodiments. Rather, each feature described in one example of an embodiment can be combined with one or more other desired features from other embodiments to produce other embodiments not described in words or with reference to the drawings.

[0077] Finally, it should be noted that the above description of the present invention and its embodiments is non-limiting, and the actual embodiments are not limited thereto. In short, if a person skilled in the art is inspired by this description and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. An atomizing diverter, characterized in that: The invention comprises an atomizing section, an atomizing particle diffusion section and a critical diversion section connected in sequence; the atomizing section comprises a plurality of atomizing flow channels for forming a mist flow, each of the atomizing flow channels is composed of a coaxial equal-diameter atomizing flow channel, a tapered atomizing flow channel and a throat atomizing flow channel arranged in sequence; the axis of each atomizing flow channel is parallel to the incoming flow direction; the atomizing particle diffusion section is composed of an atomizing particle gradually expanding section and an atomizing particle gradually contracting section; the critical diversion section comprises a plurality of critical diversion flow channels for forming a critical flow, each of the critical diversion flow channels is composed of ... The channel is composed of a coaxial constant diameter critical flow channel, a tapering section critical flow channel, a throat critical flow channel and a gradually expanding section critical flow channel arranged in sequence; the inlet of the constant diameter atomizing flow channel is connected to the inlet liquid supply pipe, the outlet of the throat atomizing flow channel is connected to the inlet end of the atomizing particle gradually expanding section, and the outlet end of the atomizing particle gradually shrinking section is connected to the inlet end of the constant diameter critical flow channel; the cross section of any position of several critical diversion flow channels is circular, and several critical diversion flow channels are arranged in a plane circle along the outlet cross section of the atomizing particle gradually shrinking section. The two-phase refrigerant flows through the multiple atomizing flow channels evenly distributed in the atomizing section, and the flow pattern is adjusted to a diffuse mist flow. The high-speed atomized particles are completely diffused in the atomizing particle gradually expanding section, and the diffused uniform mist flow is then gathered at the entrance of the critical diversion flow channel through the atomizing particle gradually contracting section. The critical flow channel at the throat of the critical diversion flow channel makes the mist gas-liquid two-phase flow refrigerant form a critical two-phase flow, cutting off the transmission of the unstable pressure wave of the downstream branch to the upstream. In the atomizing section, the mist The cross section of any position of the atomizing flow channel is circular, and several of the atomizing flow channels are evenly arranged on the same circumference and center of a circle with the center line of the atomizing section as the center, and are arranged parallel to the incoming flow direction; the inlet circles of the equal-diameter atomizing flow channels are evenly distributed on the inlet cross section of the atomizing section; the atomizing particle gradually expanding section and the atomizing particle gradually contracting section are both hollow tube structures, and the flow channel cross section profiles of the atomizing particle gradually expanding section and the atomizing particle gradually contracting section are both straight lines; the angle between the flow channel cross section profile of the atomizing particle gradually expanding section and the center line of the atomizing flow channel is α The angle between the cross-sectional profile of the atomized particle tapering section and the center line of the critical diversion channel is 15-30°. β 15-30°.

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