A design method for heat exchange compression device

Abstract

The present invention relates to a design method for a heat exchange compression device, and the design method is as follows: S1. The shape of the blade is determined by the given aerodynamic parameters of the blade and by the basic flow equation and the flow equation; S2. The impeller shaft system is simulated and calculated by dynamic simulation software, and the impeller shaft system is designed; S3. The sealing component is designed by establishing a three-dimensional model of the sealing component; S4. The dynamic model of the impeller shaft is established, and the dynamic response of the volute under load is analyzed. The heat exchange compression device designed by this method can achieve high efficiency and energy saving, and the smaller the temperature span, the higher the energy efficiency. The space occupancy rate and weight of the heat exchange compression device are reduced, and the adverse effects of the high temperature environment on the heating device are overcome.

Description

Technical Field

[0001] The invention belongs to the field of mechanical engineering, and in particular relates to a design method of a heat exchange compression device. Background Art

[0002] In view of the outstanding thermal control needs of high-power heat transmission and dissipation in future nuclear-powered spacecraft, lunar bases, laser weapons, high-power antennas, microwave payloads, etc., compressor research is carried out to meet the needs of future thermal control system upgrades and provide technical support for product autonomy in aerospace thermal control systems. The compressor consumes input work to transfer heat from low-level sources to high-level heat sources. In the existing technology, heat exchange compression devices have the disadvantages of high energy consumption, heavy weight, and high space occupancy. Summary of the invention

[0003] The object of the present invention is to solve the above-mentioned problem and provide a design method for a heat exchange compression device, the heat exchange compression device comprising a volute, a cylinder, an impeller, blades and an impeller shaft system, the impeller shaft system comprising: an impeller shaft, a sealing assembly and a bearing, the volute is connected to the cylinder, the impeller is arranged in the volute and is processed integrally with the impeller shaft, the blades are arranged on the impeller, the sealing assembly and the bearing are arranged in the cylinder and are sequentially installed on the impeller shaft in a direction away from the impeller; the design method is:

[0004] S1. Determine the shape of the blade by given aerodynamic parameters of the blade and by flow continuity equation;

[0005] S2. The impeller shaft system is simulated and calculated by dynamic simulation software, and the impeller shaft system is designed;

[0006] S3. Designing the sealing assembly by establishing a three-dimensional model of the sealing assembly;

[0007] S4. Establish a dynamic model of the impeller shaft and analyze the dynamic response of the volute under load.

[0008] According to one aspect of the present invention, in step S1, the blade design method is:

[0009] A). Firstly, a three-dimensional flow calculation model is established through the continuity equation, motion equation, energy equation and state equation;

[0010] B). Then, the streamline curvature method is used according to the assumed streamline shape, and the streamline curvature and slope are used as parameter variables. The normal or quasi-normal velocity gradient equation along the streamline is integrated along the gas flow cross section, and a new streamline shape is obtained according to the flow equation;

[0011] C) Repeating the iteration until a converged solution is obtained to obtain the shape of the blade;

[0012] D). Finally, the shape of the blade is finally determined through three-dimensional CFD numerical analysis.

[0013] According to one aspect of the present invention, in step A), the impeller flow calculation model is based on the theoretical work W done by the impeller on the unit mass of gas. th Build:

[0014] W th =c 2u u 2 -c 1u u 1

[0015] In the formula, c 2u is the absolute velocity c at the impeller blade outlet 2 Radial component velocity (m / s); u 2 Impeller blade outlet linear velocity (m / s); c 1u is the absolute velocity c at the impeller blade outlet 1 Radial component velocity (m / s); u 1 Impeller blade inlet linear velocity (m / s).

[0016] According to one aspect of the present invention, in step B), the flow equation is:

[0017]

[0018] Where, d m The unit time d t The quality of the flow passing through; q m is the mass flow rate (kg / s) and the energy equation

[0019] W tot =W th +h L +h df

[0020] Where W tot is the total power consumed by the impeller for unit mass of gas (J / kg); h L is the internal leakage loss (J / kg); h df is the wheel resistance loss (J / kg).

[0021] According to one aspect of the present invention, in step S3, the design method of the sealing component is:

[0022] A). First, a three-dimensional model of the sealing component is established, boundary conditions are clarified, and dry film contact analysis is performed on the sealing component;

[0023] B). Analyze the factors that affect the sealing performance of the sealing assembly;

[0024] C). Then, the contact stress distribution of the sealing component under no-load and loaded conditions is analyzed, the initial contact stress of the sealing component is determined by using the pressure ratio criterion, and reasonable geometric parameters are constructed;

[0025] D) Complete the design of the sealing assembly.

[0026] According to one aspect of the present invention, the sealing assembly includes a sealing frame and a sealing member, the sealing frame is provided with a groove, the sealing frame is connected to the cylinder body, one end of the sealing member is installed in the groove and closely matches the shape of the groove, and the other end closely fits the impeller shaft.

[0027] According to one aspect of the present invention, the sealing element is polytetrafluoroethylene or high molecular weight polyethylene.

[0028] According to one aspect of the present invention, in step S4, the method for analyzing the dynamic response of the volute under load is:

[0029] A). Firstly, a dynamic model of the impeller shaft is established;

[0030] B). Then, using the finite element method and multi-body dynamics theory, a finite element model analysis is performed on the impeller and the volute to obtain the modal characteristic parameters such as the natural frequency and vibration mode of the impeller shaft and the volute;

[0031] C). Through the multi-body dynamics analysis of the impeller shaft, the relevant parameters such as the gas force load and the load on the main and secondary bearings of the volute are obtained;

[0032] D). Finally, the dynamic response analysis of the volute under load is completed.

[0033] The heat exchange compression device designed by this method can achieve high efficiency and energy saving. The smaller the temperature span, the higher the energy efficiency. The space occupancy rate and weight of the heat exchange compression device are reduced, and the adverse effects of high temperature environment on heating devices are overcome. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A cross-sectional view schematically showing the heat exchange compression device;

[0035] Figure 2 A schematic perspective view of a volute;

[0036] Figure 3 A cross-sectional view schematically showing a volute;

[0037] Figure 4 A schematic three-dimensional diagram showing an impeller and blades;

[0038] Figure 5A schematic diagram showing the structure of the sealing assembly. DETAILED DESCRIPTION

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0041] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0042] Combination Figures 1 to 4 As shown, the present invention provides a design method for a heat exchange compression device, which includes a volute 1, a cylinder body 2, an impeller 3, blades 31 and an impeller shaft system 4. The volute 1 is connected to the cylinder body 2, the impeller 3 is arranged in the volute 1, the blades 31 are arranged on the outer surface of the impeller 3, and the impeller shaft system 4 is arranged in the cylinder body 2. The impeller shaft system 4 includes an impeller shaft 41, a sealing assembly 42 and a bearing 43. The sealing assembly 42 and the bearing 43 are sequentially arranged between the impeller shaft 41 and the inner wall of the cylinder body 2 in a direction away from the impeller 3. Among them, the impeller 3 and the impeller shaft 41 are processed as one piece. According to the concept of the present invention, the impeller 3 and the impeller shaft 41 are processed as one piece, which avoids the phenomenon that the impeller 3 and the impeller shaft 41 are loose under high-speed rotation. At the same time, the axial length of the entire device is reduced, and the miniaturization of the product is achieved. This heat exchange compression device adopts the structure of a centrifugal impeller to achieve the heating and compression of the refrigerant. The refrigerant vapor first enters the suction chamber in front of the impeller inlet, and then enters the impeller 3. Under the action of the blades 31, the gas rotates at high speed with the impeller 3, and at the same time, due to the centrifugal force, it expands and flows in the grooves of the blades 3, so that the pressure and speed of the gas are increased.

[0043] In this embodiment, the shape of the blade 31 is determined by the given aerodynamic parameters of the blade and by the basic flow equation and the flow equation. According to the concept of the present invention, under the action of the blade 31, the gas rotates at high speed with the impeller 3, and at the same time, due to the centrifugal force, it flows in the blade channel for expansion pressure, so the shape of the blade 31 will have a great influence on the flow of the airflow. By determining the shape of the blade 31 by the above equation, the pressure and speed of the gas can be greatly improved. In this embodiment, the impeller shaft system 4 is simulated and calculated by dynamic simulation software to guide the design of the impeller shaft system. According to the concept of the present invention, when the device is running, the impeller 3 end face intakes air, and the impeller shaft will be in a cantilever state. Therefore, the impeller shaft system 4 is subjected to load dynamic simulation analysis, and the positional relationship between the bearing support stiffness and the support point can be calculated, thereby guiding the design of the impeller shaft system 4, making the layout of the heat exchange compression device more reasonable and improving the service life. In this embodiment, the design of the sealing component 42 is completed by establishing a three-dimensional model of the sealing component 42. According to the concept of the present invention, by establishing a three-dimensional model, reasonable geometric parameters can be constructed through simulation, such as the elastic modulus of the sealing component 42, the interference amount (initial compression amount) of the sealing component 42, the contact width, the temperature and friction heat, etc., can be accurately controlled to further improve the sealing effect of the sealing component 42. In this embodiment, a dynamic model of the impeller shaft is established to analyze the dynamic response of the volute under load. According to the concept of the present invention, the flow loss of the gas at the outlet of the impeller and the diffuser is reduced, and the efficiency of the whole machine is improved.

[0044] According to the design method of the heat exchange compression device, the basic size parameters of the impeller are first calculated iteratively based on the basic flow continuity equation and the energy equation, and the impeller outlet structure parameters are calculated. The obtained parameters are returned and iterated to further optimize the impeller structure until the optimal solution is obtained. Through the above design method, the actual work done by the impeller on the unit mass of gas is improved, and the efficiency of the whole machine is improved.

[0045] According to the design method of the heat exchange compression device, firstly, a three-dimensional model of the sealing structure is established, the boundary conditions (the maximum contact stress σp of the sealing component ≥ the medium pressure p) are clarified, and the dry film contact analysis of the sealing component 42 is performed, mainly the contact stress is simulated and analyzed, and the contact stress of the sealing component in the compression state is analyzed. The factors affecting the sealing performance, such as the elastic modulus of the material, the interference amount (initial compression amount) of the sealing component 42, the contact width, temperature and friction heat, etc., are analyzed, and the contact stress distribution of the sealing component under no-load and loaded conditions is analyzed. The initial contact stress of the sealing component 42 is determined by the pressure ratio criterion, and reasonable geometric parameters are constructed. According to the concept of the present invention, through the above-mentioned design method, by considering a variety of factors affecting the seal, the material selection and structural design of the sealing component 42 are further determined, which prevents rework, saves costs, and further improves the sealing performance of the sealing structure.

[0046] Combination Figure 5 As shown, according to an embodiment of the present invention, the sealing assembly 42 includes a sealing frame 44 and a sealing member 45, and the sealing frame 42 is connected to the cylinder body 2. In this embodiment, one end of the sealing member 45 is connected to the groove of the sealing frame 44 and closely matches the shape of the groove, and the other end is closely fitted on the impeller shaft. According to the concept of the present invention, a mixed lubrication flow state is constructed, and on the basis of ensuring reliable sealing, the sealing life is extended and the trouble-free working time of the whole machine is improved.

[0047] Combination Figure 5 As shown, in this embodiment, the sealing member 45 is polytetrafluoroethylene or high molecular polyethylene. According to the concept of the present invention, polytetrafluoroethylene or high molecular polyethylene has strong high and low temperature resistance, excellent chemical stability and electrical insulation performance, which can ensure that the sealing member 45 will not be damaged in special use environments, improve the sealing performance, and polytetrafluoroethylene or high molecular polyethylene is low in price, which reduces the manufacturing cost of the heat exchange compression device.

[0048] The above is only one embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A design method for a heat exchange compression device, It is characterized in that The heat exchange compression device comprises a volute (1), a cylinder (2), an impeller (3), blades (31) and an impeller shaft system (4), wherein the impeller shaft system (4) comprises an impeller shaft (41), a sealing assembly (42) and a bearing (43), wherein the volute (1) and the cylinder (2) are connected, wherein the impeller (3) is arranged in the volute (1) and is processed integrally with the impeller shaft (41), wherein the blades (31) are arranged on the impeller (3), and wherein the sealing assembly (42) and the bearing (43) are arranged in the cylinder and are sequentially mounted on the impeller shaft (41) in a direction away from the impeller; wherein the design method is as follows: S1. By giving the aerodynamic parameters of the blade (31), and determining the shape of the blade (31) by the flow continuity equation, the design method of the blade (31) is: A). According to the theoretical work W done by the impeller on unit mass of gas th Constructing and establishing the impeller flow calculation model; B). Then, the streamline curvature method is used according to the assumed streamline shape, and the streamline curvature and slope are used as parameter variables. The normal or quasi-normal velocity gradient equation along the streamline is integrated along the gas flow cross section, and a new streamline shape is obtained according to the flow equation; C) Repeating the iteration until a converged solution is obtained to obtain the shape of the blade (31); D) finally determining the shape of the blade (31) through three-dimensional CFD numerical analysis; S2. The impeller shaft system (4) is simulated and calculated by dynamic simulation software, and the impeller shaft system (4) is designed; S3. By establishing a three-dimensional model of the sealing component (42), the sealing component (42) is designed. The design method of the sealing component (42) is: A). First, a three-dimensional model of the sealing component (42) is established, boundary conditions are clarified, and dry film contact analysis is performed on the sealing component (42); B) further analyzing the factors affecting the sealing performance of the sealing assembly (42); C) Then analyzing the contact stress distribution of the sealing assembly (42) under no-load and loaded conditions, determining the initial contact stress of the sealing assembly using a pressure ratio criterion, and constructing reasonable geometric parameters; D) completing the design of the sealing assembly (42); S4. Establish a dynamic model of the impeller shaft (41) and analyze the dynamic response of the volute (1) under load.

2. The design method according to claim 1, It is characterized in that In step A) of step S1, the impeller flow calculation model is constructed according to the theoretical work Wth done by the impeller on a unit mass of gas: W th =c 2u u 2 -c 1u u 1 In the formula, c 2u is the absolute velocity c at the impeller blade outlet 2 The radial component velocity is in m / s; u 2 Impeller blade outlet linear velocity, in m / s; c 1u is the absolute velocity c at the impeller blade outlet 1 The radial component velocity is in m / s; u 1 The impeller blade inlet linear velocity, its unit is m / s.

3. The design method according to claim 1, It is characterized in that In step B) of step S1, The flow equation is: Where, d m The unit time d t The mass of flow passing through the inner chamber; the energy equation is: W tot =W th +h L +h df Where, mass flow rate q m The unit is kg / s; W tot It is the total power consumption of the impeller on unit mass of gas, and its unit is J / kg; h L is the internal leakage loss, its unit is J / kg; hdf is the wheel resistance loss, its unit is J / kg.

4. The design method according to claim 1, It is characterized in that The sealing assembly (42) comprises a sealing frame (44) and a sealing member (45), wherein the sealing frame (44) is provided with a groove, the sealing frame (44) is connected to the cylinder body (2), one end of the sealing member (45) is installed in the groove and closely matches the shape of the groove, and the other end is closely fitted on the impeller shaft (41).

5. The design method according to claim 4, It is characterized in that The sealing member (45) is made of polytetrafluoroethylene or high molecular weight polyethylene.

6. The design method according to claim 1, It is characterized in that In step S4, the method for analyzing the dynamic response of the volute (1) under load is: A). Firstly, a dynamic model of the impeller shaft (41) is established; B) Then, using the finite element method and multi-body dynamics theory, a finite element model analysis is performed on the impeller (3) and the volute (1) to obtain the natural frequency and vibration mode characteristic parameters of the impeller shaft (41) and the volute (1); C) by multi-body dynamics analysis of the impeller shaft (41), the gas force load and the parameters related to the loads on the main and secondary bearings of the volute (1) are obtained; D). Finally, the dynamic response analysis of the volute (1) under load is completed.

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