ABSTRACT

Pulsating heat pipe (PHP) is a unique device for the management of thermal systems having brilliant chances of wide spread applications because of its simple design, low cost, and excellent ability to transfer heat. Numerous research investigations have been carried out for enhancement of heat transfer performances of PHPs taking into account the operation mechanisms and working fluids. The main purpose of this review is to provide a brief summary on the use of ferrofluids as one class of magnetic nanofluids in the PHPs and its impact on enhancement of heat transfer. The influence of working fluid, number of turns, and inclination angle has also been discussed on flow pattern and thermal performances of a PHP. The ferrofluids offer significant heat transfer enhancement due to higher thermal conductivity in the presence of magnetic fields, lower viscosity, and surface tension compared to conventional working fluids and ordinary nanofluids. The ferrofluids exhibit strong influence on the flow regime at increased heat input leading to higher vapor generation which can transform slug plug flow to annular flow resulting in augmented heat transfer rate. The application of magnetic field facilitates the mixing of flow in a turbulent manner which results in increased heat transfer by convection in the vicinity of the magnet. Thus, significantly high heat transfer can be achieved using ferrofluids with higher concentration as working fluids. The recent developments in the application of PHPs in solar heating, electronic cooling and waste heat recovery systems are discussed in the present review. Simultaneously, the challenges and future scope in the application of ferrofluids in PHPs have been highlighted for further investigation.

摘要

脉动热管 (PHP) 是一种用于管理热系统的独特设备，由于其设计简单、成本低和传热能力出色，因此具有广泛应用的绝佳机会。考虑到运行机制和工作流体，已经进行了大量研究调查以提高 PHP 的传热性能。本综述的主要目的是简要总结铁磁流体作为 PHP 中一类磁性纳米流体的使用及其对增强传热的影响。还讨论了工作流体、圈数和倾角对 PHP 的流动模式和热性能的影响。由于在磁场存在下具有更高的热导率，铁磁流体提供了显着的传热增强，与传统工作流体和普通纳米流体相比，具有更低的粘度和表面张力。铁磁流体在增加热输入时对流动状态有很大影响，导致更高的蒸汽产生，这可以将段塞流转化为环流，从而提高传热率。磁场的应用有利于以湍流方式混合流动，这导致通过磁体附近的对流增加热传递。因此，使用具有更高浓度的铁磁流体作为工作流体可以实现显着高的传热。本综述讨论了 PHP 在太阳能加热、电子冷却和废热回收系统中应用的最新进展。同时，