ABSTRACT

Displaced enhancement devices are inserts positioned inside pipes that increase the heat transfer rate. This study presents an original application of an inverse analysis technique to experimental infrared temperature data to estimate the local convective heat flux for forced convection flow in a pipe in which this kind of device is present. Butterfly-shaped inserts have been investigated to determine their local and global thermal performance. The insert produces a distortion in the velocity profile that causes an irregular distribution of the wall heat flux along the circumferential coordinate. Several studies have investigated displaced enhancement devices, but they generally considered only the overall heat transfer performance. The present work aims to fill this gap by presenting and testing an experimental procedure for estimating the local convective heat flux in pipes equipped with this type of insert. The experimental results obtained in the present investigation are useful for the design of heat exchangers for processes in which product temperature must be carefully controlled (e.g. pharmaceutical and food industries). These types of devices induce significant spatial variation of the heat flux, and quantitative data of this aspect is of primary importance.

摘要

位移增强装置是位于管道内部的插入件，可提高传热速率。这项研究提出了逆分析技术在实验红外温度数据上的原始应用，以估计存在这种设备的管道中强制对流的局部对流热通量。已经对蝴蝶形刀片进行了研究，以确定它们的局部和整体热性能。插入件会在速度分布中产生变形，从而导致壁热通量沿圆周坐标的不规则分布。几项研究已经研究了位移增强装置，但他们通常只考虑整体传热性能。本工作旨在通过提出和测试一种实验程序来填补这一空白，该程序用于估计配备有这种插入件的管道中的局部对流热通量。在本研究中获得的实验结果可用于设计必须仔细控制产品温度的过程（例如制药和食品工业）的热交换器的设计。这些类型的设备会引起热通量的显着空间变化，这方面的定量数据至关重要。