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

本研究项目旨在研究循环液池中水平管式换热器中壳程沸腾的热工水力学特性，以及在直流式进料系统中的热工水力学特性。实验将在使用制冷剂R-113的现有流动回路中进行。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，使壳体/管束的几何形状可以通过插入件从釜式再沸器改变为直通式浸没蒸发器的几何形状。管束中的管子将被电加热，并用热电偶进行测量。测量将包括整个管束的压力分布、空泡率和平均液体速度，当作为釜式再沸器操作时，管壳和管束之间空间的液体速度，测试段功率和壁温。建立了热工水力学的二维双流体数值模型，对实验装置进行了模拟。一旦通过比较实验数据和预测数据，以及将计算机模拟与全尺寸捆绑的工业数据进行比较来验证该模型，那么将研究创新的流体-流体热交换器。后面的这些推测性研究将调查各种几何和操作条件。这项研究旨在开发有关壳侧沸腾和两相流的新数据，并整合前两个项目的结果，以获得整体管束性能。它将为研究不受过去壳程沸腾换热器实践限制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.