An Experimental and Numerical Investigation of Shellside Boiling in Horizontal Tube Bundles

本课题拟研究在循环液池中的水平管式换热器和一次直通进料系统中壳侧沸腾的热工力学。实验将在现有的流动回路中使用制冷剂R-113进行。将设计和构造一个正方形、直列和等边三角形水平管束的半片模型，这样，通过插入，壳体/管束的几何形状可以从釜式再沸器的形状改变为一次通过式浸没式蒸发器的形状。束中的管子将被电加热，并用热电偶进行测量。测量将包括压力分布、空隙率和整个管束的平均液体速度、作为釜式再沸器运行时壳体和管束之间空间的液体速度、测试段功率和壁温。将建立一个二维、双流体的热水力学数值模型来模拟实验装置。一旦该模型通过对比实验数据和实验预测数据，以及将计算机模拟与全尺寸管束的工业数据进行比较得到验证，那么创新的流体-流体热交换器将被研究。后一种推测性研究将研究各种几何和操作条件。本研究旨在开发壳侧沸腾和两相流的新数据，并整合之前两个项目的结果，以获得管束的整体性能。它将为研究不受过去壳侧沸腾热交换器实践约束的创新设计铺平道路，并将展示未来研究活动的方向。

This research project proposes to investigate the thermal hydraulics of shellside boiling in a horizontal tube heat exchanger in a recirculating liquid pool as well as in a once- through feed system. Experiments will be run in an existing flow loop using refrigerant R-113. A model of half of a slice of a square, inline and an equilateral triangular horizontal tube bundle will be designed and constructed such that with an insert the shell/bundle geometry can be changed from that of a kettle reboiler to that of a once-through submerged evaporator. The tubes in the bundle will be electrically heated and instrumented with thermocouples. Measurements will include the pressure distribution, void fraction and mean liquid velocity throughout the bundle, liquid velocities in the space between the shell and the bundle when operating as a kettle reboiler, test section power and wall temperatures. A two-dimensional, two-fluid numerical model of the thermal hydraulics will be developed to simulate the experimental setup. Once this model has been verified by comparing the experimental and predicted data from this experiment and by comparing computer simulations against industry data from full scale bundles, then innovative fluid-to-fluid heat exchangers will be studied. These latter speculative studies will investigate a variety of geometric and operating conditions. This research is intended to develop new data on shellside boiling and two-phase flow and to integrate the results from two previous projects to obtain overall tube bundle performance. It will pave the way for studying innovative designs unconstrained by past practice for heat exchangers with shellside boiling, and will demonstrate where future research activities should be directed.