Numerical Investigation of Nanoparticles Shape Impacts on Thermal Energy Transfer and Flow Features of Nanofluid Impingement Jets

2021 ◽  
Vol 143 (11) ◽  
Author(s):  
Behrang Asghari Shirvani ◽  
Javad Sodagar ◽  
Farshid Eynijengheshlaghi ◽  
Ahmad Arabkoohsar
Keyword(s):  
Reynolds Number ◽  
Energy Transfer ◽  
Pressure Drop ◽  
Thermal Energy ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Working Fluid ◽  
Energy Transfer Rate ◽  
Spherical Nanoparticles ◽  
Impingement Jet

Abstract Today, energy transfer enhancement techniques have received much attention for design and manufacturing more efficient systems in various industries such as automotive, computers, electronics, and so forth. One way to achieve high-efficiency cooling systems is to use impingement jet cooling. In the present study, a numerical study has been conducted on nanofluid impingement jet in the vertical position to investigate the fluid flow characteristics and thermal energy transfer features. The working fluid in this study is a nanofluid with water–ethylene glycol mixture as base fluid and nanoparticles of boehmite alumina. The flow is considered to be laminar, steady-state, two-dimensional, symmetrically axial, for which the finite volume method is used to solve the equations. The effect of the Reynolds number variations, the volume fraction of nanoparticle, and different nanoparticle shapes (including spherical, plate, blade, cylindrical, and brick shapes) on thermophysical features of the flow are studied. The results reveal that the increasing Reynolds number and the increasing volume fraction of nanoparticles improves the thermal energy transfer rate. The highest Nusselt number leads to a maximum of energy transfer related to nanofluids with platelet and cylindrical nanoparticles, while the lowest thermal energy transfer rate is related to nanofluids containing spherical nanoparticles. Moreover, it is illustrated that nanofluids with platelets nanoparticles, because of their higher effective viscosity compares to other nanofluids, experience the highest pressure drop and those of with spherical nanoparticles show the lowest pressure drop.

scholarly journals CFD Study Based on Effect of Employing the Single-Walled Carbon Nanotube (SWCNT) and Graphene Quantum Dots (GQD) Nanoparticles and a Particular Fin Configuration on the Thermal Performance in the Shell and Tube Heat Exchanger

CFD letters ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 37-60
Author(s):  
Mohammadreza Hasandust Rostami ◽  
Barat Ghobadian ◽  
Gholamhassan Najafi ◽  
Ali Motevali ◽  
Nor Azwadi Che Sidik
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Concentration ◽  
Working Fluid ◽  
Tube Heat Exchanger ◽  
Average Temperature

In this research, the thermal attributes of shell and finned tube heat exchanger such as thermal efficiency, pressure drop, heat transfer rate and average temperature in the tube side of heat exchanger with using the different volume concentration of nanoparticles (SWCNT and Graphene quantum dot) at the various Reynolds number by applying either fin blades and without fin blades have been conducted numerically. In this heat exchanger the hot fluid or nanofluid flows in the tube section and cold fluid or pure water moves in the shell side. As regarding to results obtained the majority of thermal characteristics like heat transfer rate, pressure drop and effectiveness enhanced with augmentation of Reynolds number and increasing of volume concentration of nanofluids to 1% volumetric of working fluid whereas at the higher volume concentrations of nanoparticles (upper from 1% volumetric) the thermal properties of heat exchanger decreased generally. Also pressure drop intensifies with increment of Reynolds number and volume concentration of nanoparticles that at higher Reynolds number the effects of nanoparticles on the pressure drop were more noticeable. The average temperature of heat exchanger in the end section of inside tubes increased with augmentation of Reynolds number and nanoparticles. Finally, according to the results obtained in this study, most impression on the thermal attributes enhancement was found by employing of finned tubes compared to other factor which this factor increased heat transfer rate of heat exchanger by almost 188% also the effects of nanoparticles at the high levels of volume concentration especially for 5% of SWCNT nanoparticle on the pressure drop obtained about 80% compared to the base fluid.

Extraction of energy transfer rate constants from the pulsed laser generated thermal lens spectrometer signal

1982 ◽  
Vol 80 ◽  
pp. 433-436 ◽  
Author(s):  
R.T. Bailey ◽  
F.R. Cruickshank ◽  
R. Guthrie ◽  
D. Pugh ◽  
I.J.M. Weir
Keyword(s):  
Energy Transfer ◽  
Thermal Lens ◽  
Rate Constants ◽  
Transfer Rate ◽  
Pulsed Laser ◽  
Energy Transfer Rate

scholarly journals Research on the design and application of capillary heat exchangers for heat pumps in coastal areas

2021 ◽  
Vol 42 (3) ◽  
pp. 333-348
Author(s):  
Zhenpeng Bai ◽  
Yanfeng Li ◽  
Jin Zhang ◽  
Alan Fewkes ◽  
Hua Zhong
Keyword(s):  
Renewable Energy ◽  
Energy Transfer ◽  
Heat Exchanger ◽  
Heat Pump ◽  
Transfer Rate ◽  
Coastal Areas ◽  
Heat Energy ◽  
Low Carbon ◽  
Energy Transfer Rate ◽  
Pump System

This study investigated the optimal design of a capillary heat exchanger device for the heat pump system and its innovative engineering application in a building. The overall aim was to use a capillary heat exchanger to obtain energy in coastal areas for promoting renewable energy in low-carbon building design. Initially, the main factors affecting the efficiency of the capillary heat exchanger were identified, a mathematical model was then established to analyse the heat transfer process. The analysis showed the flow rate and the capillary length are the key factors affecting the efficiency of the capillary heat exchanger. Secondly, to optimize the structural design of the capillary heat exchanger, the heat energy transfer is calculated with different lengths of the capillary under various flow rates in summer and winter conditions, respectively. Thirdly, a typical building is selected to analyse the application of the capillary heat exchanger for extracting energy in the coastal area. The results show the performance of the selected capillary heat exchanger heat pump system, in winter, the heat energy transfer rate is 60 W/m2 when the seawater temperature is 3.7 °C; in summer, the heat energy transfer rate is 150 W/m2 when the seawater temperature is 24.6 °C. Finally, the above field test results were examined using a numerical simulation model, the test and simulation results agree with each other quite well. This paper is conducive in promoting the development of the capillary heat exchanger heat pump as an innovative sustainable technology for net-zero energy and low carbon buildings using renewable energy in coastal areas. Practical application: A recently proposed capillary heat exchanger is used as an energy extraction and utilisation device to obtain energy in coastal areas for promoting renewable energy in low-carbon building design. This paper explores the application of a capillary heat exchanger as both cold and heat sources for application in typical low-rise buildings. The analysis of the heat energy transfer rate of a typical low-rise building located in a coastal area in summer and winter provides guidance for the application of capillary heat exchangers.

Improvement of Er3+:4I11/2→Ce3+:2F5/2 energy transfer rate in Er3+/Ce3+ co-doped TeO2–ZnO–Na2O–Nb2O5 glasses

2009 ◽  
Vol 129 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Yaxun Zhou ◽  
Jun Wang ◽  
Shixun Dai ◽  
Tiefeng Xu ◽  
Qiuhua Nie ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Transfer Rate ◽  
Energy Transfer Rate ◽  
Co Doped

Single-Phase Heat Transfer and Pressure Drop of Water Cooled Inside Horizontal Smooth Tubes in the Transitional Flow Regime

2010 ◽  
Author(s):  
Josua P. Meyer ◽  
Leon Liebenberg ◽  
Jonathan A. Olivier
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Transition Region ◽  
Heat Exchangers ◽  
Operating Conditions ◽  
Transitional Flow ◽  
Working Fluid ◽  
Tube Heat Exchanger ◽  
Smooth Tubes

Heat exchangers are usually designed in such a way that they do not operate in the transition region. This is usually due to a lack of information in this region. However, due to design constraints, energy efficiency requirements or change of operating conditions, heat exchangers are often forced to operate in this region. It is also well known that entrance disturbances influence where transition occurs. The purpose of this paper is to present experimental heat transfer and pressure drop data in the transition region for fully developed and developing flows inside smooth tubes using water as the working fluid. The use of different inlet disturbances were used to investigate its effect on transition. A tube-in-tube heat exchanger was used to perform the experiments, which ranged in Reynolds numbers from 1 000 to 20 000, with Prandtl numbers being between 4 and 6 while Grashof numbers were in the order of 105. Results showed that the type of inlet disturbance could delay transition to a Reynolds number as high as 7 000, while other inlets expedited it, confirming results of others. For heat transfer, though, it was found that transition was independent of the inlet disturbance and all commenced at the same Reynolds number, 2 000–3 000, which was attributed to secondary flow effects.

scholarly journals Fluid Flow and Entropy Generation Analysis of Al2O3–Water Nanofluid in Microchannel Plate Fin Heat Sinks

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 739 ◽  
Author(s):  
Hao Ma ◽  
Zhipeng Duan ◽  
Liangbin Su ◽  
Xiaoru Ning ◽  
Jiao Bai ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Aspect Ratio ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Microchannel Plate ◽  
Heat Sinks ◽  
Entropy Generation Rate ◽  
Nanoparticle Volume Fraction ◽  
Channel Aspect Ratio

The flow in channels of microdevices is usually in the developing regime. Three-dimensional laminar flow characteristics of a nanofluid in microchannel plate fin heat sinks are investigated numerically in this paper. Deionized water and Al2O3–water nanofluid are employed as the cooling fluid in our work. The effects of the Reynolds number (100 < Re < 1000), channel aspect ratio (0 < ε < 1), and nanoparticle volume fraction (0.5% < Φ < 5%) on pressure drop and entropy generation in microchannel plate fin heat sinks are examined in detail. Herein, the general expression of the entropy generation rate considering entrance effects is developed. The results revealed that the frictional entropy generation and pressure drop increase as nanoparticle volume fraction and Reynolds number increase, while decrease as the channel aspect ratio increases. When the nanoparticle volume fraction increases from 0 to 3% at Re = 500, the pressure drop of microchannel plate fin heat sinks with ε = 0.5 increases by 9%. It is demonstrated that the effect of the entrance region is crucial for evaluating the performance of microchannel plate fin heat sinks. The study may shed some light on the design and optimization of microchannel heat sinks.

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