仿肺泡结构换热器流动传热特性及熵综合分析

Research on flow heat transfer and entropy analysis of heat ex-changer with imitation alveolar structure

中文关键词: 仿生  仿肺泡结构  熵产分析  3D打印  强化换热。

英文关键词: bionic  mimic alveolar pore structure  entropy generation analysis  3D printing  enhanced heat exchange.

中文摘要:

      针对航空发动机热管理系统有限空间内低阻高效换热的需求，设计了一种仿肺泡结构换热器，建立了三维模型开展流动传热特性数值模拟，并基于热力学第二定律，以熵产数作为指标对不同结构和流动参数下的换热器进行熵的评价分析。结果表明：仿肺泡结构换热器具有比表面积大、压降小等明显优势，同等空间和相同重量下可以显著提高换热且压力损失可控，并改善温度场均匀性，具有良好的流动换热特性。利用熵分析方法建立了流动与换热间的物理关联，阐明了仿肺泡结构换热器优良流动换热特性的物理本质是在传热熵产一定时，降低压力熵产，并发现管中心距、壁厚与空气侧流量是熵产的主要影响因素。同时，应用3D打印技术建立了模型试验件开展了实验验证。实验值与数值模拟结果较好地吻合，证明了仿肺泡结构换热器的技术可行及分析方法的准确。

英文摘要:

      Aiming at the de mand of low resistance and high efficiency heat transfer in the limited space of aero-engine thermal management system, a simulated alveolar heat exchanger was designed. A three-dimensional model was established to carry out numerical simulation of flow heat transfer characteristics. Based on the second law of thermodynamics, entropy production number was used to evaluate and analyze the entropy of heat exchangers with different structure and flow parameters. The results show that: The heat exchanger with imitation alveolar structure has obvious advantages such as large specific surface area and small pres-sure drop, which can significantly improve heat transfer and control pressure loss under the same space and weight, improve the uniformity of temperature field, and have good flow heat transfer characteristics. En-tropy analysis method establishes the physical correlation between flow and heat transfer. The physical es-sence of the excellent flow heat transfer characteristics of the quasi-alveolar structure heat exchanger is to reduce the pressure entropy production when the heat transfer entropy production is certain, and it is found that the main factors affecting the entropy production are tube center distance, wall thickness and air side flow. At the same time, 3D printing technology was used to establish a model test piece to carry out exper-imental verification. The experimental results are in good agreement with the numerical simulation results, which proves the technical feasibility and the accuracy of the analysis method.