| Currently, in order to solve the contradiction of spatial arrangement inside the engine compartment, facilitating collaborative optimization of aerodynamic resistance and heat transfer efficiency, detached vehicular cooling module was indicated as one of the important technical means, while the study of law of cooling flow and heat transfer, synergistic match inside the detached vehicular cooling module was still in its initial stage. The research was still focus on traditional cooling module, and the systematic theories and methods on this new type detached vehicular cooling module had not been established.In this thesis, a numerical simulation model of vehicular cooling module was established and verified by experiment, to explore its performance evaluation and application principles, to thoroughly study the matching rule between the cooling fan and the heat exchanger module as well as the collaborative feature among a number of heat exchangers, finally to form systemio analysis method and collaborative design matching theory for detached vehicular cooling module.The main research contents include:1) Study on numerical method of establishing detached cooling module modelStudy the numerical method of cooling fan and heat exchanger appropriate to vehicular, cooling module, increasing the accuracy of numerical fan model and heat exchanger model. On the basis of it, the numerical model of vehicular cooling module was carried on.2) Test verification of numerical detached cooling module modelSet up vehicular detached cooling module simulated test system, verified the validity of numerical detached cooling module model by experiment, including the flow and heat transfer performance of detached cooling module, visual experiment validation of flow field distribution inside the cooling module.3) Study on matching and analysis method of detached cooling moduleStudy the impact of the variation of matching parameters on the aerodynamic performance and the match characteristics of cooling module with single heat exchanger; Study the impact of the position and quantity of air intakes on the cooling performance and the match characteristics of cooling module with heat exchanger module in serial structure; Study the impact of relative position of heat exchangers on the cooling performance and the match characteristics of cooling module with heat exchanger module in parallel structure.4) Study on performance evaluation and analysis method of detached cooling moduleEvaluation and analysis system of detached cooling module was established based on the indexes of effective drag coefficient, fan efficiency, cooling efficiency, fan and heat exchanger matching curve. And the evaluation and analysis of detached cooling module with various structures and types were carried on, the scope of application and characteristic of each parameter was founded.5) Study on collaborative features between heat exchangers in detached cooling moduleStudy the collaborative feature between heat exchangers in detached cooling module, including the general rules of aerodynamic drags in detached cooling module with serial heat exchanger module were distributed in serial, which in detached cooling module with parallel heat exchanger module were distributed in parallel. The coupling effect of flow and heat transfer between heat exchangers to the overall performance of cooling module was studied as well.Through the above research, the following conclusions were obtained:1) The numerical method study of cooling module found that for heat exchanger model, when employing porous medium model based on performance test data, and revising the porous parameters, its numerical simulation accuracy is improved. For fan model, when the roughness of blade surface is modified with the wall function, the numerical result was more close to the test data.2) Through the research of performance test, the test values of the aerodynamic resistance were in good agreement with the simulated results. Through visual experimental study of micro flow field found that, period of transient wind velocity, inlet surface velocity distribution and the vortex inside the cooling module coincide with simulated results well.3) The numerical study of matching parameters between fan and heat exchanger inside the cooling module with single heat exchanger showed that while there was certain relative angle and relative area ratio between fan and heat exchanger, the cooling module had the best aerodynamic performance. Based on it, for cooling module with single fan and heat exchanger, the dual matching method between fan and heat exchanger was put forward.4) The numerical study of the impact of the position and quantity of air intakes on the cooling performance in cooling module with serial heat exchanger module showed that they could optimize the performance, but the decisive factor is the matching characteristic between fan and heat exchanger module. In addition, the study found that the mutual interference between heat exchangers was obvious, the performance of heat exchanger in back row was suppressed by that of front critically.5) The numerical study of cooling module with parallel heat exchanger module found that when the heat exchangers were arranged with opposed position, the cooling module has the best flow and heat transfer performance, and there also existed flow collaborative characteristics between heat exchangers, the active control of cooling air flow could be achieved by control the relative dimension of heat exchangers under the same fan speed.6) Through the evaluation and analysis of detached cooling module with different structures and types, it was found that effective drag coefficient was applicable for evaluating matching degree of integration; The fan efficiency is applied to evaluate the power consumption of the cooling module. Fan and heat exchanger matching curve can be used to evaluate the matching rationality between fan and heat exchanger modules of different structures, while the cooling efficiency was fitted to evaluate the performance of the cooling module. Thus, The evaluation and analysis of the cooling module should be combined with various evaluation parameters. |
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