相变储热换热器设计及强化换热机理研究

发布时间：2018-01-16 02:25

本文关键词：相变储热换热器设计及强化换热机理研究　出处：《中国地质大学(北京)》2015年博士论文　论文类型：学位论文

【摘要】：板式和管壳式相变储热换热器是相变储热换热器研究的热点。但是,目前对这两种储能换热器强化换热的机理性研究还不够；对储/释热的工况影响研究单一；相变材料组合(m-PCMs)的无量纲化研究也鲜有报道；将相变储热换热器真正应用到实际的工程,来对工业余热进行回收利用的事例更是少之又少。本文主要针对以上问题,从换热器结构、相变材料组合和换热工况三个方面对锯齿板式和管壳式相变储热器的换热情况进行模拟研究,并根据管壳式换热器机械强度高、拆卸方便等特点,设计了新型的管壳式相变储热换热器,并通过高低温换热器串级回收柴油机余热。对锯齿板式相变储能换热器的相变传热问题建立数学模型和定解条件,并与实验结果进行对比,验证了模型的可靠性。分析了锯齿板的形貌对锯齿板相变储能换热器储热性能的影响,并通过相变材料组合强化锯齿板相变储能换热器的换热性能,研究了相变温度对换热的影响。提出能量百分数概念,并对相变材料组合的储/释热参数进行了无量纲化。提出进口功率边界条件,系统分析了在一定进口功率条件下,进口温度和进口速度对锯齿板式相变储能换热器换热的影响；并研究了在给定进口功率条件下,周期性变化的进口速度的周期性大小和振幅大小对锯齿板式相变储能换热器的影响,得出锯齿板相变储能换热器具有优良的“稳温”性能。对管壳式相变储能换热器的相变传热问题建立了数学模型和定解条件,通过与实验结果对比,验证了选取模型的可靠性。分析了相变材料管的排列方式对换热的影响,并用梯级储热的形式来提高热量的回收率。研究了在一定进口功率的条件下,进口温度和进口速度对梯级储热的管壳式相变储能换热器换热的影响；并研究了周期性变化进口速度的周期性大小和振幅大小对梯级储热的管壳式相变储热换热器的影响,得出管壳式相变储能换热器也具有良好的“稳温”性能。搭建了柴油机余热回收实验平台,设计了新式高/低温管壳式相变储能换热器,研究了储/释能过程中换热器内部的温度变化情况,并通过热力学第一定律和(火积)原理分析了其储能过程,发现管体的储能效果不能忽略。
[Abstract]:Plate and shell heat storage heat exchangers are the hot spots in the research of phase change heat storage heat exchangers. However, the mechanism of these two heat storage heat exchangers is not enough. Single study on the effect of storage / heat release on the operating conditions; The dimensionless study of phase change material combination (m-PCMs) is also rarely reported. The application of phase change heat storage heat exchanger to the actual engineering, to recover industrial heat is very rare. This paper mainly aims at the above problems, from the structure of the heat exchanger. The heat transfer of sawtooth plate type and tube shell type phase change storage heater is simulated from three aspects of phase change material combination and heat transfer condition, and according to the characteristics of tube and shell heat exchanger, such as high mechanical strength, convenient disassembly and so on. A new type of shell and tube heat storage heat exchanger is designed, and the heat transfer of diesel engine is recovered by cascade heat exchanger at high and low temperature. The mathematical model and solution condition of phase change heat transfer of sawtooth plate type phase change heat storage heat exchanger are established. Compared with the experimental results, the reliability of the model is verified, and the influence of the morphology of the saw tooth plate on the heat storage performance of the phase change heat exchanger is analyzed. The effect of phase transition temperature on heat transfer was studied by strengthening the heat transfer performance of phase change heat exchanger with zigzag plate, and the concept of energy percent was put forward. The storage / heat release parameters of PCMs are dimensionless. The boundary conditions of inlet power are proposed, and the system is analyzed under certain inlet power conditions. The influence of inlet temperature and inlet velocity on heat transfer of sawtooth plate phase change heat storage heat exchanger; The influence of the periodic magnitude and amplitude of the periodically varying inlet velocity on the sawtooth plate phase change heat exchanger is also studied under the condition of the inlet power. It is concluded that the sawtooth plate phase change heat exchanger has excellent "stable temperature" performance. The mathematical model and the solution conditions of the phase change heat transfer problem of the tubular and shell type phase change energy storage heat exchanger are established, and the results are compared with the experimental results. The reliability of the selected model is verified. The influence of the arrangement of phase change material tubes on heat transfer is analyzed, and the heat recovery rate is improved by using the form of cascade heat storage. The influence of inlet temperature and inlet velocity on heat transfer of tubular and shell heat storage heat exchanger with cascade heat storage; The influence of periodic variation of inlet velocity and amplitude on the heat storage heat exchanger with tubular and shell phase change was studied. It is concluded that the tube-shell phase change heat storage heat exchanger also has good "stable temperature" performance. The experimental platform of diesel engine waste heat recovery is built, and a new high / low temperature tubular and shell type phase change energy storage heat exchanger is designed. The change of temperature in heat exchanger during energy storage / release is studied. The energy storage process of heat exchanger is analyzed by the first law of thermodynamics and the principle of fire product. It is found that the energy storage effect of tube can not be ignored.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB34;TQ051.5

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