THEORETICAL INVESTIGATION ON THE EFFECT OF NANO FLUIDS ON HEAT TRANSFER CHARACTERISTICS IN A HEAT PIPE (original) (raw)

Heat Transfer Enhancement in Heat Pipe Using Nanofluid – A Review

— For enhancement of heat transfer in heat pipe, Nano fluid found vital role and a new frontier in various engineering applications. This paper reviews and summarizes the work on heat pipes using nano fluids as a working medium. Various types of nano particle with different base fluids as proved its potential to improve thermal properties of working medium in heat pipe. The effect of filling ratio, volume fraction of nano practices on thermal performance in various kinds of heat pipe with different base fluids under various operating conditions has been discussed. Mechanism of enhancement of heat transfer after utilization of nano fluids in heat pipe has been explained. Also, influence of dimensionless on thermal resistance in terms of correlation has been studied. This paper discusses relativity of total heat resistance between the heat pipe with nano fluid and with existing fluids. Focusing towards the application this paper suggests the suitability of heat pipes in various heat generation problems.

INVESTIGATION ON THERMAL PERFORMANCE OF HEAT PIPE USING NANOFLUID: A REVIEW

IJAERD, 2018

Nanofluids have been the subject of intensive study worldwide since pioneering researchers recently discovered the anomalous thermal behaviour of these fluids. Comprehensive research work on heat transfer in heat pipe using nanofluids have been experimentally and theoretically investigated in recent years by various researchers. The suspended nanoparticles effectively enhance the heat transfer characteristics and the transport properties of base fluids in heat pipes. The objective of this paper is to present an overview of literature dealing with influence of various factors such as heat pipe tilt angle, charged amount of working fluid, nanoparticle type, size and concentration, mass/ volume fraction & its effect on the thermal efficiency, heat transfer capacity & reduction in thermal resistance.

A REVIEW ON HEAT TRANSFER ENHANCEMENT STUDIES OF HEAT PIPES USING NANOFLUIDS

Heat pipe is a special type of heat exchanger that transfers large amount of heat due to the effect of capillary action and phase change heat transfer principle. Recent development in the heat pipe includes high thermal conductivity fluids like nanofluids, sealed inside to extract the maximum heat. This paper reviews, influence of various factors such as heat pipe tilt angle, charged amount of working fluid, nanoparticles type, size, and mass/volume fraction and its effect on the improvement of thermal efficiency, heat transfer capacity and reduction in thermal resistance. The nanofluid preparation and the analysis of its thermal characteristics also have been reviewed.

Heat transfer mechanisms in heat pipes using nanofluids – A review

Experimental Thermal and Fluid Science, 2018

Heat pipes are compact and efficient heat exchangers which are widely used in a large number of thermal devices. Researchers were attracted towards the application of nanofluids in heat pipes due to its superior thermo physical properties. They used nanofluids as working fluid in heat pipes and noticed significant changes in thermal performance. In present study authors summarize the research outcomes of various experimental and numerical studies. It also provides an overview of heat transfer mechanisms responsible for the change in thermal performance of heat pipes. Heat transfer mechanisms depend upon, type of heat pipes, nanofluids characteristics, design and operating parameters of heat pipes etc. All the parameters have their own individual as well as the combined effect on thermal performance. Authors have drawn the attention of research community to explore the dependency of all parameters on each other.

A Review of Performance of Heat Pipe with Nanofluids

With the modern era of miniaturization of equipments, heat pipes have attracted major attention in the field of heat transfer. Nanofluids also have attracted a notable attention in recent days due to its superior heat transport properties. This review aim to compile the effect of nanofluid in heat pipes. Performance of different nanoparticles and different base-fluids are investigated. Most of the papers reviewed here reported an enhancement in performance of heat pipes. Existence of an optimum concentration of nanoparticles in base fluid was also reported. Paper also presents a perspective on possible research application.

Evaluation of Heat Transfer Mechanisms in Heat Pipe Charged with Nanofluid

Arabian Journal for Science and Engineering, 2019

The nanofluid is a colloidal solid-liquid mixture obtained by the dispersing nanoparticles with a high heat transfer coefficient in the base fluid. In general, metal, metal oxide, ceramic and magnetic nanoparticles are used in nanofluids. The nanoparticles suspended in the base fluid of heat pipes effectively increased the heat transfer rate and thermal conductivity properties of the base fluid. The nanofluids have been found to be acting much better for some problems such as sedimentation, erosion, clogging and pressure drop compared to common slurries. The energy transfer is carried out by two-phase heat transfer mechanism in heat pipes. There are many parameters and factors that have an effect in the boiling heat transfer coefficient. It is not easy to understand the positive and negative changes caused by nanofluids in this complex heat transfer mechanism. The surface geometry is a significant indicator on the boiling heat transfer mechanism. Investigation into nanofluid effects besides the surface geometry is very important in the experimental studies. In addition, it is known that nanofluids change the properties of the heater surface, apart from the thermophysical properties. The synthesis methods of nanofluids are presented in this article. Then, the physical and chemical mechanisms determining the long-term stability of nanofluids are explained in detail. Finally, some useful information about the use of nanofluids in heat pipes and pool boiling of nanofluids is given. The presented study also describes the pool boiling mechanism of nanofluids to understand the positive effects of nanofluids on the heat pipes heat transfer mechanism.

An investigation of the thermal performance of cylindrical heat pipes using nanofluids

… Journal of Heat and Mass Transfer, 2010

In this work, a two-dimensional analysis is used to study the thermal performance of a cylindrical heat pipe utilizing nanofluids. Three of the most common nanoparticles, namely Al 2 O 3 , CuO, and TiO 2 are considered as the working fluid. A substantial change in the heat pipe thermal resistance, temperature distribution, and maximum capillary heat transfer of the heat pipe is observed when using a nanofluid. The nanoparticles within the liquid enhance the thermal performance of the heat pipe by reducing the thermal resistance while enhancing the maximum heat load it can carry. The existence of an optimum mass concentration for nanoparticles in maximizing the heat transfer limit is established. The effect of particle size on the thermal performance of the heat pipe is also investigated. It is found that smaller particles have a more pronounced effect on the temperature gradient along the heat pipe.

A comprehensive study of the performance of a heat pipe by using of various nanofluids

Science Direct, 2017

In this paper, a two-dimensional numerical model is developed to simulate the performance of a heat pipe using various nanofluids. The effect of different nanofluids (prepared using alumina, copper oxide, and silver nanoparticles) at different concentrations and particle diameters on the performance of heat pipe is also studied by through finite volume method. The obtained results show that using a nanofluid instead of water leads to the increased thermal efficiency and reduction in heat at wall of the heat pipe. Also, the temperature difference between the evaporator and the condenser is a function of input power; this means that by an increase in the input capacity, the temperature difference between the evaporator and the condenser increases. It was observed that the use of nanofluid reduces the axial-flow pressure of the fluid inside the wick. As a result, the transmission of fluid flow inside the wick from the condenser to the evaporator is easily done with the cost of using a nanofluid. Moreover, with an increase in thermal capacity, fluid pressure drop becomes maximum and thus temperature difference between the evapora-tor and the condenser increases.

www.journals.saintgits.org Review paper A Review of Performance of Heat Pipe with Nanofluids

2016

Copyright © 2014 IJRIST. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. With the modern era of miniaturization of equipments, heat pipes have attracted major attention in the field of heat transfer. Nanofluids also have attracted a notable attention in recent days due to its superior heat transport properties. This review aim to compile the effect of nanofluid in heat pipes. Performance of different nanoparticles and different base-fluids are investigated. Most of the papers reviewed here reported an enhancement in performance of heat pipes. Existence of an optimum concentration of nanoparticles in base fluid was also reported. Paper also presents a perspective on possible research application.

Thermal performance of cylindrical heat pipe using nanofluids

Journal of thermophysics …, 2010

Acylindrical copper heat pipe with a 19.5mmouter diameter and a 400.0mmlength was filled with three different working fluids and tested for different heat inputs in the range of 100–250 W. The working fluids tested were de-ionized water, silver–water colloid, and copper water. Experimental results showed that the wall temperature reduction obtained was 3–27C. The efficiency of the heat pipe was enhanced by 14% as compared with the heat pipe filled with the base fluid. Furthermore, it was found that an increase in the metal fraction in copper–water nanofluids lead to enhancement in thermal efficiency of the heat pipe. Thermal conductivities of copper–water nanofluids were measured, showing a 30% enhancement with a 0.1 wt%of copper nanoparticles.