非对称人字形波纹板式换热器自激振荡流动与强化换热机理研究

项目名称： 非对称人字形波纹板式换热器自激振荡流动与强化换热机理研究

项目编号： No.51506034

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 能源与动力工程

项目作者： 韩怀志

作者单位： 哈尔滨工程大学

项目金额： 21万元

中文摘要： 强化换热技术的应用使得换热器逐渐向高效型、紧凑型发展。目前，针对板式换热器强化换热技术的研究，普遍考察稳态的流动与传热特性，而未深入研究流体弹性激励下振荡强化换热机理和影响因素。本申请以非对称人字形波纹板为研究对象，针对板间波纹驱动所产生的自激振荡流动特征，结合实验和理论进行振荡强化换热机理研究。嵌入介质物性随温度和压力的变化的分布函数，建立瞬态大涡模拟(LES)数值模型，并采用实验方法验证模型的精确性。基于该模型进行时均和脉动壁表面特征数分布规律的研究，并建立壁表面特征数的经验关联式；进行涡结构演化规律及“类振荡”现象的研究，揭示振荡流强化换热机理；追踪层流向自激振荡流过渡时的临界雷诺数，获得波纹腔体内产生自激振荡的评价指标；采用克里金结合微遗传算法进行优化设计研究，获得不同工况下的最优结构。本课题旨在阐明振荡流作用下的强化换热机制，对于高效换热器的优化设计与应用具有重要的理论意义。

中文关键词： 人字形波纹板换热器；自激振荡流；强化换热；数值模拟；优化设计

英文摘要： Heat exchangers have been developed toward high-efficient and compacted by application of heat transfer enhancement technology. At present, researching on heat transfer enhancement technology for plate heat exchanger mainly investigates steady flow and heat transfer characteristic. However, the heat transfer enhancement mechanism and effect factors induced by self-sustained oscillatory flow haven’t been deep excavated. Considering the self-sustained oscillatory flow characteristic in asymmetrical chevron type plate, the heat transfer enhancement mechanism of self-sustained oscillatory flow is investigated by combining experimental and theory analysis. Embedded distribution function of physical property change with various temperature and pressure, transient Large Eddy Simulation (LES) model has been constructed. Experimental method is used to verify the LES model. Based on this model, the distribution law of time averaged and pulsating quantity wall surface characteristic numbers will be investigated. Empirical correlation for the wall surface characteristic numbers will be constructed. The evolution principle of vortex structure and the phenomenon of “analogous oscillation” will be investigated to reveal the heat transfer enhancement mechanism of self-sustained oscillatory flow. The critical Reynolds number will be tracked when flow regime transits from laminar to self-sustained oscillatory flow. The assessment criteria producing self-sustained oscillatory in wave cavity will be obtained. The optimization design is investigated by Kriging and Micro Genetic Algorithm (MGA) to obtain optimal structure of different working condition. Our research works aim to clarify the heat transfer enhancement mechanism induced by self-sustained oscillatory flow, this possesses important theory meaning for optimal design and application of high efficient heat exchanger.

英文关键词： Chevron type plate heat exchanger;Self-sustained oscillatory flow;Heat transfer enhancement;Numerical simulation;Optimal design