【作者】 蒋君之；

【导师】 陈焕新；

【作者基本信息】 华中科技大学 ， 制冷及低温工程， 2011， 硕士

【摘要】 本课题来源于国家科技支撑计划项目(2008BAJ12B03):建筑物(群)全天候耦合能量传递优化控制及节能关键技术。本文主要集中于满液式太阳能蒸汽发生系统中蒸汽发生器传热过程的研究以及蒸汽发生器的结构设计,研究如何在保证太阳能蒸汽发生器汽化率的前提下,减小传热介质输送功率以及换热面积,进而提高蒸汽发生器的效率,降低蒸汽发生器的成本。本文的研究工作主要包括以下几个部分:(1)分析该太阳能蒸汽发生器在运行工况下的热流密度大致范围,以此为基础,研究管束外沸腾在该热流密度范围内管束效应大小及其影响因素,从提高汽化率的角度,选择大间距满液式作为蒸汽发生器的结构类型;(2)对换热管数量、长度、管内流速与导热油输送功率间的关系进行研究,在汽化率要求一定的情况下,确定各参数的合理取值,以减小输送功率和换热面积,从而提高蒸汽发生器效率;(3)对蒸汽发生器换热过程各部分热阻进行分析,确定蒸汽发生器传热强化的主要途径为降低管内对流换热热阻,然后对对流换热强化机理和泵的输送功率进行理论分析,推导出传热强化的综合评价准则PEC,提出了蒸汽发生器传热强化的方案。更多还原

【Abstract】 The technology of generating steam of middle or high temperature using solar energy include two types: direct and indirect. To generate steam of high temperature higher than 300℃, the direct method is mainly applied; to generate steam of temperature lower than 300℃, the indirect method is also applied. The indirect method is that the heat-transfer medium circulates in the solar collector tubes to collect solar energy, and then flows into the steam generator to heat water to generate steam. Current research on the indirect method is mainly about the process of collecting solar energy. The research of this thesis is mainly on the heat transfer and economical efficiency of the flooded steam generator. The main content of the research is as follows:First, the heat flow density of the steam generator is analyzed, based on the heat flow density, the bundle effect in nucleate boiling outside tube bundle is researched, to improve vaporization rate, flooded-type with large gap of tubes is selected;Second, the relation between the number of the tubes, the length of the tubes, the flow velocity in the tubes and the conveying power consumption of the heat transfer medium is researched, on condition that the vaporization rate is fulfilled, the value of these parameters is determined to decrease conveying power consumption and heat transfer area;The thermal resistance of each sections of heat transfer is analyzed, then the thermal resistance of convection inside the tubes is discovered to be the main element of the total thermal resistance, then the performance evaluation principle of heat transfer augment is deduced, the methods of heat transfer augment is put forward.更多还原