塔式太阳能熔盐吸热器传热特性及?分析

Thermal and Exergy Performance of Molten Salt External Cylindrical Receiver of Solar Power Towers

该文建立了塔式光热电站圆柱形外露管式吸热器(external cylindrical receiver,ECR)的二维传热模型。重点分析了非均匀入射能流、入射能流总功率、环境风速以及吸热管尺寸等运行设计参数对吸热器表面的温度及热损分布、热效率、压降特性和[火用]效率的影响。结果表明:辐射和对流热损主要集中在吸热器后半部的高温区域,若镜场投入辐射集中在熔盐进口区域,将导致熔盐升温过快,高温区域增大,造成更大的热损失;小管径吸热器有更高的热效率以及更小的环境对流热损,但同时会带来更大的压降损失,在直径小于2cm后压降的增幅尤为明显。考虑环境风速与运行功率的影响,[火用]效率随管径显著变化,并存在最优值,随着入射能流总功率的增大,[火用]效率最优值随管径增大而增大。该文的工作可为目前主流商业化塔式电站用外露管柱式吸热器的设计计算以及辐射能流分布的优化提供理论参考。

In this paper, a detailed 2D model of the external cylindrical receiver was presented. The characteristics of thermal efficiency, pressure drop and exergy efficiency, which is influenced by the operating and design parameters such as non-uniform heat flux, total incident power, ambient wind speeds and pipe diameters, were analyzed. The results show that radiation heat loss and convective heat loss mainly concentrate upon the high temperature region at the rear half of the receiver. If the heat flux is concentrated on the area of inlet,will cause the molten salt temperature rises too fast and led to a greater heat loss due to the high temperature region of the tube plate become larger. The small tube gets a better heat transfer efficiency and a smaller convection heat loss, but at the same time, it causes a greater pressure drop. When the diameter is less than 2 cm, the increase of pressure drop is particularly obvious. Combined pressure drop and thermal efficiency, the best exergy efficiency achieved, with the increase of the total incident power, the optimal value of exergy efficiency is appears in the bigger pipe case. The analysis of the related mechanism in this paper can provide a reference for the design and optimization of the radiative heat flux of the external cylindrical receiver.