Heat Transfer Augmentation in Heat Exchanger by using Nanofluids and Vibration Excitation - A Review

Abstract

Nanofluids are used in heat exchanger system as efficient heat transfer fluids to improve heat transfer performance by passive method. Besides, another special active technique by implementing the low or high frequency vibration, which was used in heat exchanger to enhance the heat transfer performance. This paper reviews the heat transfer augmentation in heat exchanger by using nanofluids, vibration excitation of low and high frequency vibration. The use of nanofluids in heat exchanger system can provide better effective thermal conductivity compared to the conventional coolants. The presence of nanosize particles in nanofluids performed better mixing flow with higher thermal properties compared to pure fluids. Additionally, the active method by inducing low and high frequency vibration technology was applied in heat exchanger system. The heat transfer augmentation by vibration excitation was resulted from the mitigation of the fouling resistance on the surface of the tube wall. It was found that vibration excitation not only increase the heat transfer rate, but also might be a solution for fouling reduction. Hence, there is a great potential of using nanofluids together with vibration excitation simultaneously in heat exchanger system to improve the heat transfer performance.

Optimum Utilisation of CuO Nanofluid in Flat Plate Solar Collector

“…From the results, it can be said that the collector efficiency is directly proportional to the Reynolds number. The results agree with the findings of researchers listed in reference [5]. However, the researchers [5] achieved higher efficiency, although the trend of the graph is very similar.…”

“…The results agree with the findings of researchers listed in reference [5]. However, the researchers [5] achieved higher efficiency, although the trend of the graph is very similar. As shown in Figure 13, the efficiency of FPSC with CuO nanofluid is higher than with water as collector fluid.…”

“…As the particle volume concentration increases, the thermal conductivity of nanofluid increases due to a higher concentration of nanoparticle. However, the nanofluid thermal conductivity decreases with increasing nanoparticle sizes, and a similar trend was also observed in previous findings [5]. The figure shows that the thermal conductivity of 25 nm CuO nanofluid was the highest compared to all other higher diameters CuO nanofluid.…”

“…The metallic nanoparticles are usually aluminium (Al), copper (Cu), and iron (Fe) while the metallic oxide nanoparticles are copper oxide (CuO), titanium dioxide (TiO2), alumina (Al2O3), titanium dioxide (TiO2) and silicon dioxide (SiO2). These nanofluids have been utilised in many research areas such as in heat exchanger system, microchannel/fin system of cooling electronic devices, machining process in the manufacturing system, cold storage system, and cooling system in the car radiator for the enhancement of the heat transfer process and the development of the nanofluids [5][6][7][8][9][10][11][12][13]. Also, these nanofluids can be utilised solar collectors to enhance the thermal performance of the solar collector [14].…”

Effect of TiO2/MO Nano-lubricant on Energy and Exergy Savings of an Air Conditioner using Blends of R22/R600a

“…Also, nanoparticles used in the base fluid tend to improve the thermo-physical properties (thermal conductivity, viscosity, etc.) of the base fluid significantly [27]. Commonly, it is acknowledged that due to the existence of solid particles, thermo-physical properties of the traditional coolant enhanced.…”