Numerical study on thermal performance of an air-cooled heat exchanger: Effects of hybrid nanofluid, pipe arrangement and cross section

2018 ◽  
Vol 164 ◽  
pp. 615-628 ◽  
Author(s):  
Ali Karimi ◽  
Masoud Afrand
Keyword(s):  
Heat Exchanger ◽  
Cross Section ◽  
Thermal Performance ◽  
Numerical Study ◽  
Hybrid Nanofluid ◽  
Air Cooled Heat Exchanger

Numerical study of a crossflow heat exchanger to investigate thermal performance using nanofluids

2019 ◽  
Author(s):  
Jaed Al Nahian ◽  
Partha Pratim Pandit ◽  
Mohammad Arif Hasan Mamun
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Numerical Study

A Numerical Study of Flow and Temperature Maldistribution in a Parallel Microchannel System for Heat Removal in Microelectronic Devices

2012 ◽  
Author(s):  
Manoj Siva ◽  
Arvind Pattamatta ◽  
Sarit Kumar Das
Keyword(s):  
Heat Exchanger ◽  
Cross Section ◽  
Design Theory ◽  
Cooling System ◽  
Search Algorithm ◽  
Numerical Study ◽  
Heat Removal ◽  
Flow Distribution ◽  
Microchannel Cooling ◽  
Flow Maldistribution

A common assumption in basic heat exchanger design theory is that fluid is distributed uniformly at the inlet of the exchanger on each fluid side and throughout the core. However in reality, uniform flow distribution is never achieved in a heat exchanger and is referred to as flow maldistribution. Flow maldistribution is generally well understood for the macrochannel system. But it is still unclear whether the assumptions underlying the flow distribution in conventional macrochannel heat exchangers hold good for microchannel system. In this regard, extensive numerical simulations are carried out in a ‘U’ type parallel micro-channel system in order to study flow and heat transfer maldistribution and validated with in-house experimental data. A detailed parametric analysis is carried out to characterize flow maldistribution in a microchannel system and to study the effect of geometrical factors such as number of channels, n, Area of cross section of the channel Ac, manifold cross section area Ap, and flow parameter such as Reynolds number, Re, on the pressure and temperature distribution. In order to minimize the variation in pressure and to reduce temperature hot spots in the microchannel, a Response surface based surrogate approximation (RSA) and a gradient based search algorithm are used to arrive at the best configuration of microchannel cooling system. A three level factorial design involving three parameters namely Ac/Ap, Re, n are considered. The results from the optimization indicate that the case of n = 5, Ac/Ap = 0.12, and Re = 100 is the best possible configuration to alleviate flow maldistribution and hotspot formation in microchannel cooling system.

Thermal Performance Enhancement of an Industrial Shell and Tube Heat Exchanger

2015 ◽  
Author(s):  
Fadi A. Ghaith ◽  
Ahmed S. Izhar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Thermal Performance ◽  
Numerical Study ◽  
Thermal Design ◽  
Shell Side ◽  
Tube Heat Exchanger ◽  
Shell And Tube

This paper aims to enhance the thermal performance of an industrial shell-and-tube heat exchanger utilized for the purpose of cooling raw natural gas by means of mixture of Sales gas. The main objective of this work is to provide an optimum and reliable thermal design of a single-shelled finned tubes heat exchanger to replace the existing two- shell and tube heat exchanger due to the space limitations in the plant. A comprehensive thermal model was developed using the effectiveness-NTU method. The shell-side and tube-side overall heat transfer coefficient were determined using Bell-Delaware method and Dittus-Boelter correlation, respectively. The obtained results showed that the required area to provide a thermal duty of 1.4 MW is about 1132 m2 with tube-side and shell-side heat transfer coefficients of 950 W/m2K and 495 W/m2K, respectively. In order to verify the obtained results generated from the mathematical model, a numerical study was carried out using HTRI software which showed a good match in terms of the heat transfer area and the tube-side heat transfer coefficient.

A Numerical Study of Flow and Temperature Maldistribution in a Parallel Microchannel System for Heat Removal in Microelectronic Devices

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
V. Manoj Siva ◽  
Arvind Pattamatta ◽  
Sarit Kumar Das
Keyword(s):  
Heat Exchanger ◽  
Cross Section ◽  
Design Theory ◽  
Cooling System ◽  
Search Algorithm ◽  
Numerical Study ◽  
Heat Removal ◽  
Flow Distribution ◽  
Microchannel Cooling ◽  
Flow Maldistribution

A common assumption in basic heat exchanger design theory is that fluid is distributed uniformly at the inlet of the exchanger on each fluid side and throughout the core. However, in reality, uniform flow distribution is never achieved in a heat exchanger and is referred to as flow maldistribution. Flow maldistribution is generally well understood for the macrochannel system. But it is still unclear whether the assumptions underlying the flow distribution in conventional macrochannel heat exchangers hold good for microchannel system. In this regard, extensive numerical simulations are carried out in a “U” type parallel microchannel system in order to study flow and heat transfer maldistribution and validated with in-house experimental data. A detailed parametric analysis is carried out to characterize flow maldistribution in a microchannel system and to study the effect of geometrical factors such as number of channels, n, Area of cross section of the channel Ac, manifold cross section area Ap, and flow parameter such as Reynolds number, Re, on the pressure and temperature distribution. In order to minimize the variation in pressure and to reduce temperature hot spots in the microchannel, a response surface based surrogate approximation and a gradient based search algorithm are used to arrive at the best configuration of microchannel cooling system. A three level factorial design involving three parameters namely Ac/Ap, Re, n are considered. The results from the optimization indicate that the case of n = 7, Ac/Ap = 0.69, and Re = 100 is the best possible configuration to alleviate flow maldistribution and hotspot formation in microchannel cooling system.

scholarly journals Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 881
Author(s):  
Mashhour A. Alazwari ◽  
Mohammad Reza Safaei
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Thermal Performance ◽  
Heat Removal ◽  
Hybrid Nanofluid ◽  
Distilled Water ◽  
Reference Case ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Shell And Tube

In this study, thermal performance and flow characteristics of a shell and tube heat exchanger equipped with various baffle angles were studied. The heat exchanger was operated with distilled water, and a hybrid nanofluid at three concentrations of 0.04% and 0.10% of GNP-Ag/water within Reynolds numbers ranged between 10,000 and 20,000. The thermophysical properties of nanofluid varied with temperature and nanoparticles’ concentration. The baffle angles were set at 45°, 90°, 135°, and 180°. Results showed that the calculated Nusselt number (Nu) could be improved by adding nanoparticles to the distilled water or increasing the fluid’s Reynolds number. At a low Re number, the Nu corresponding to baffle angle of 135° was very close to that recorded for the angle of 180°. At Re = 20,000, the Nu number was the highest (by 35% compared to the reference case), belonging to a baffle angle of 135°. Additionally, results related to friction factor and pressure drop showed that more locations with fluid blocking were observed by increasing the baffle angle, resulting in increased pressure drop value and friction. Finally, the temperature streamlines counter showed that the best baffle angle could be 135° in which maximum heat removal and the best thermal performance can be observed.

scholarly journals NUMERICAL STUDY OF THE HIGH-SPEED BYPASS EFFECT ON THE AERO-THERMAL PERFORMANCE OF A PLATE-FIN TYPE HEAT EXCHANGER

2017 ◽  
Vol 22 (1) ◽  
pp. 67-80
Author(s):  
Jun Seok Lee ◽  
Minsung Kim ◽  
Man Yeong Ha ◽  
June Kee Min
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
High Speed ◽  
Numerical Study
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