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为了研究航空发动机1次表面换热器流动换热性能,基于传热单元数法并结合其结构特性,建立了换热器热力学设计方法并对经典热力学公式进行了对比分析。同时针对适用于航空发动机的4种不同结构形式1次表面换热器(直通道逆流型和1 5°,30°及45°叉流型),在真实工况下的流动换热特性开展了数值模拟研究。通过对比不同结构换热器在不同工况下的流动换热特点,可以为一次表面换热器芯体核心部件的优化设计提供设计依据和方法。基于数值计算结果,对比分析了不同交错角度θ对换热器的换热性能与流动特性的影响。结果表明:对于直通道逆流换热器,整个换热器内部温度有规律均匀分布;对于叉流换热器,由于波纹板片呈一定角度交替放置,内部流动复杂,局部存在明显的涡流强化换热,气体流动通道内的速度、温度分布极不均匀。随着交错角度的不断增大,叉流换热器的换热性能不断增强,但其冷热两侧压降也大幅增大。
In order to study the heat transfer performance of a surface heat exchanger of aeroengine, the thermodynamic design method of the heat exchanger was established based on the numerical method of heat transfer unit and its structural characteristics. The classical thermodynamic formulas were compared and analyzed. At the same time, four kinds of heat exchangers (direct channel counterflow, 1 5 °, 30 ° and 45 ° cross-flow type) suitable for aero-engine with 4 different structures were developed. Under normal operating conditions, Numerical simulation research. By comparing the heat transfer characteristics of heat exchangers with different structures under different operating conditions, it can provide the design basis and method for the optimization design of the core components of the primary surface heat exchanger. Based on the numerical results, the influence of staggered angle θ on the heat transfer performance and flow characteristics of the heat exchanger was analyzed. The results show that for the cross-flow countercurrent heat exchanger, the internal temperature of the heat exchanger is regularly and uniformly distributed. For the cross-flow heat exchanger, due to the corrugated plates being placed at an angle, the internal flow is complicated and the vortex enhancement Heat, gas flow channels within the speed, temperature distribution is extremely uneven. With the increasing staggering angle, the heat transfer performance of the cross-flow heat exchanger is continuously enhanced, but the pressure drop on both sides of the hot and cold pipes also increases greatly.