CAE Technology in the design of heat exchanger for

2022-08-12
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CAE Technology in vehicle heat exchanger design

Application CAE technology designers can find design defects and modify them in the early stage of product design, avoiding the situation of unqualified performance, delayed development cycle and high product cost after the completion of product design. This design has been more and more used in the development of vehicles and parts. According to statistics, the research and development time of Toyota Camry has been shortened by 10 months after the adoption of CAE virtual prototype technology, the human investment has been reduced by 20%, the research and development cost has been reduced by 30%, and the number of sample vehicles has been reduced by 65%. 0 another successful example is Ford company, which has reduced the number of tests of each new car from 300 to 80 after the adoption of CAE technology

The emergence of CAE technology is the comprehensive requirement of product diversification, intelligence and complexity, and it is a comprehensive process including product design, engineering analysis, data management, testing, simulation and manufacturing. The application of CAE technology requires a carrier manual control button box! The operation is more humanized. This carrier is CAE software. CAE software is a comprehensive knowledge intensive information product formed by combining computational mechanics, computational mathematics, related engineering science, engineering management and modern computing technology. It can be divided into special software and general software. Special software is developed for specific types of objects for performance analysis, prediction and optimization. In recent years, large companies at home and abroad have devoted themselves to the development of special software according to their own products, which has greatly improved the efficiency of product design. General software refers to the software that analyzes, simulates, predicts, evaluates and optimizes the physical and mechanical properties of various types of objects to achieve product technological innovation, such as finite element software such as NASTRAN, ANSYS, ABAQUS, Marc and old eas, and finite difference software such as fluent. The main objects of these software are components, including structural stiffness, strength analysis, nonlinear and thermal field calculation; Another example is that the main objects of system simulation software such as KULI and Flowmaster are subsystems or systems. The above software usually includes optimization design module, Structural parameters can be optimized (these software can realize the organic combination of part analysis and system analysis through the interface.

the application of CAE Technology in the design of vehicle heat exchanger

vehicle heat exchanger mainly includes: engine oil cooler, intercooler, radiator and EGR cooler in the engine, as well as evaporator and condenser in the vehicle air conditioning system. The independent research and development of vehicle heat exchanger is also an important part of China's independent automobile brand Important aspects. CAE technology is widely used in the research and development process of foreign vehicle heat exchanger enterprises, while domestic enterprises are still in the initial stage. The application of CAE Technology in vehicle heat exchanger mainly includes the following aspects: Simulation of heat transfer and flow performance of heat exchanger, reliability simulation of heat exchanger, system simulation, and special design software of heat exchanger

Application of CAE Technology in the simulation of heat transfer and flow performance of heat exchanger

attention should be paid to the heat transfer and flow characteristics of heat exchanger with dowel pins inserted, which is the primary design requirement of heat exchanger, so it is also the most widely used aspect of CAE Technology in the design and application of heat exchanger] the performance simulation of heat exchanger is to apply general engineering analysis software to calculate the heat transfer performance and fluid flow resistance of heat exchanger, Not only the overall performance of the heat exchanger can be obtained, but also the visualization of the fluid flow field, pressure field and temperature field inside the heat exchanger can be realized, and the details of temperature, pressure and flow rate at any point in the heat exchanger that cannot be obtained by the test method can be obtained (see Figure 1). In addition, the influence of the structural parameters of the heat exchanger on the local flow field and temperature field of the heat exchanger can be understood, which provides a theoretical basis for the structural modification and the determination of the optimal scheme

Application of CAE Technology in the reliability analysis of heat exchanger

the working environment of vehicle heat exchanger is relatively poor, especially in the application of heavy machinery, so the reliability of heat exchanger is also an important guarantee for the normal operation of heat exchanger. CAE technology simulation of heat exchanger reliability mainly includes: static analysis, dynamic analysis and mechanical/thermal fatigue analysis of heat exchanger

static analysis is mainly static structural strength analysis, through which the distribution of structural stress and displacement can be obtained (see Figure 2), so as to judge whether the structure is safe and reliable under the action of working load, which parts of the structure will produce stress concentration and insufficient strength, so as to improve the design of the structure

analysis, transient dynamic analysis and spectral analysis. The common analysis in heat exchanger is steady-state dynamic analysis, including modal analysis and harmonic response analysis. Modal analysis is used to determine the vibration characteristics of structures or components in the design, that is, the natural frequency and mode shape (see Figure 3). Modal analysis and cyclic symmetric structural modal analysis can be carried out on prestressed structures. Harmonic response analysis is a technique used to analyze the continuous periodic response generated by the continuous periodic load in the structural system and determine the steady-state response of the linear structure when it bears the load that changes sinusoidally with time. Its purpose is to calculate the response value versus frequency curve of the structure at several frequencies (see Figure 4). Through harmonic response analysis, designers can predict the continuous dynamic characteristics of the structure, so as to verify whether the design can overcome the harmful effects caused by resonance, fatigue and other forced vibration

in addition, the heat exchanger has been in the working condition of mechanical vibration caused by vehicle bumps and engine operation and alternating cold and heat caused by start/stop for a long time, so mechanical/thermal fatigue damage is also a common failure form of heat exchanger. Fatigue analysis is based on the above analysis, introducing the mechanical/thermal fatigue performance of materials into the calculation, analyzing the cycle limit of weak points, so as to predict the service life of heat exchanger components (see Figure 5)

Application of CAE Technology in system simulation

engine cooling system, lubrication system and air conditioning system are networks composed of many pipelines and components through various connection modes. The components in the whole network are coupled with each other, and their physical parameters cannot be solved alone, so it is necessary to solve all physical quantities of the whole system simultaneously; Therefore, system simulation is particularly important for OEMs or vehicle manufacturers. In order to solve these problems, scholars at home and abroad have compiled effective system analysis software based on the fluid network method, such as commercial software KULI (Fig. 6) and Flowmaster. They are complete system simulation software packages for engineering. For complex physical problems, they can quickly and effectively establish accurate system models, carry out simulation calculation and result analysis, and evaluate whether the system parameters match. Flowmaster software includes a series of carefully designed modules for various system pipe flow calculations, which can help engineers quickly and accurately simulate and calculate various complex fluid systems. Domestic vehicle and main engine manufacturers (such as FAW, Yuchai, etc.) have successfully introduced it into the development of engine cooling system, lubrication system and air conditioning system

it is worth mentioning that through its own interface program, the system simulation software can output the calculation results to the component simulation software as the boundary conditions of the component simulation model; At the same time, it can also accept the results of component simulation software, so as to achieve more accurate system simulation

the application of CAE Technology in the special design software of heat exchanger

commercial software can analyze the common problems of heat exchanger components or systems. However, because the products of their respective manufacturers have their own particularity, many foreign heat exchanger developers, such as Delphi, proliance and so on, have developed special heat exchangers according to their own products, which is difficult to seize the strategic commanding height; 3. Exchanger design software with low resource utilization capacity. These software are applicable to the series products of specific companies, and can analyze, predict and optimize the performance at the beginning of product design, which greatly improves the efficiency of product design. The development of mature special design software is not achieved overnight. It requires the accumulation of a large number of basic data and experience. 2. The main types are stable and the annual total amount is adjusted. At present, some domestic manufacturers have also actively invested in this research

cae technology can effectively change the traditional design ideas and methods in the field of vehicle heat exchanger, and improve the design ability and efficiency. Therefore, the application level of CAE technology will become an important symbol to measure the technological innovation ability of an enterprise. CAE technology will show greater value in the design of vehicle heat exchanger products, and will have a broader application space. (end)

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