scholarly journals Numerical Exploration of Influence of Phase Changing Material in Heat Transfer Augmentation in the Double Tube Heat Exchanger

2018 ◽  
Vol 7 (3.27) ◽  
pp. 162
Author(s):  
C Gnanavel ◽  
R Saravanan ◽  
M Chandrasekaran
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Volume Fraction ◽  
Heat Transfer Fluid ◽  
Storage Device ◽  
Liquid Volume ◽  
Inlet Temperature ◽  
Transition Flow ◽  
Liquid Volume Fraction ◽  
Tube Heat Exchanger

The double tube heat exchanger is a device in which the inner tube carries the hot fluid.  Phase Changing Material is the energy storage device is used for Solar heater applications to maintain the constant temperature, in the present study of this work is CFD Analysis of plain tube heat exchanger with Phase Changing Material (PCM) and without Phase Changing Material (PCM), Charging time, liquid volume fraction with the various Heat Transfer Fluid (HTF) inlet temperature 70, 75, 80 deg Celsius and various flow conditions of laminar flow of 2000 Re, Transition flow of 4000 Re and Turbulent flow of 10,000 Re  

Turbulent flows in a spiral double-pipe heat exchanger

2019 ◽  
Vol 30 (1) ◽  
pp. 39-53 ◽  
Author(s):  
Zhe Tian ◽  
Ali Abdollahi ◽  
Mahmoud Shariati ◽  
Atefeh Amindoust ◽  
Hossein Arasteh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Turbulent Flows ◽  
Heat Exchangers ◽  
Volume Fraction ◽  
Inlet Temperature ◽  
Content Type ◽  
Tube Heat Exchanger ◽  
Double Pipe ◽  
Pipe Heat

Purpose This paper aims to study the fluid flow and heat transfer through a spiral double-pipe heat exchanger. Nowadays using spiral double-pipe heat exchangers has become popular in different industrial segments due to its complex and spiral structure, which causes an enhancement in heat transfer. Design/methodology/approach In these heat exchangers, by converting the fluid motion to the secondary motion, the heat transfer coefficient is greater than that of the straight double-pipe heat exchangers and cause increased heat transfer between fluids. Findings The present study, by using the Fluent software and nanofluid heat transfer simulation in a spiral double-tube heat exchanger, investigates the effects of operating parameters including fluid inlet velocity, volume fraction of nanoparticles, type of nanoparticles and fluid inlet temperature on heat transfer efficiency. Originality/value After presenting the results derived from the fluid numerical simulation and finding the optimal performance conditions using a genetic algorithm, it was found that water–Al2O3 and water–SiO2 nanofluids are the best choices for the Reynolds numbers ranging from 10,551 to 17,220 and 17,220 to 31,910, respectively.

scholarly journals Thermal Analysis of the Effects of Multifaceted Conditions on Performance of Shell-and-Tube Heat Exchanger

2021 ◽  
Vol 6 (1) ◽  
pp. 69-75
Author(s):  
Taiwo O. Oni ◽  
Ayotunde A. Ojo ◽  
Daniel C. Uguru-Okorie ◽  
David O. Akindele
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Parallel Flow ◽  
Hot Water ◽  
Inlet Temperature ◽  
Fiber Glass ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Shell And Tube ◽  
Flow Configurations

A shell-and-tube heat exchanger which was subjected to different flow configurations, viz. counter flow, and parallel flow, was investigated. Each of the flow configurations was operated under two different conditions of the shell, that is, an uninsulated shell and a shell insulated with fiber glass. The hot water inlet temperature of the tube was reduced gradually from 60 oC to 40 oC, and performance evaluation of the heat exchanger was carried out. It was found that for the uninsulated shell, the heat transfer effectiveness for hot water inlet temperature of 60, 55, 50, 45, and 40 oC are 0.243, 0.244, 0.240, 0.240, and 0.247, respectively, for the parallel flow arrangement. For the counter flow arrangement, the heat transfer effectiveness for the uninsulated shell are 2.40, 2.74, 5.00, 4.17, and 2.70%, respectively, higher than those for the parallel flow. The heat exchanger’s heat transfer effectiveness with fiber-glass-insulated shell for the parallel flow condition with tube hot water inlet temperatures of 60, 55, 50, 45, and 40 oC are 0.223, 0.226, 0.220, 0.225, and 0.227, respectively, whereas the counter flow condition has its heat transfer effectiveness increased by 1.28, 1.47, 1.82, 1.11, and 1.18%, respectively, over those of the parallel flow.

Numerical Simulations of the Fluid Flow and Heat Transfer during a Solidification Phase Change of a Polymer in a Die

2010 ◽  
Vol 97-101 ◽  
pp. 2736-2743
Author(s):  
Shi Xiong Ren ◽  
Sha Sha Dang ◽  
Tao Lu ◽  
Kui Sheng Wang
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Liquid Volume ◽  
Liquid Volume Fraction ◽  
Three Dimensional Models ◽  
Lower Temperature ◽  
Thermal Oil

Three-dimensional models of heat transfer have been established and numerically solved using a commercial software package, Fluent, in order to obtain distributions of temperature, velocity, pressure, and liquid volume fraction of the polymer. The influences of the boundary conditions on the phase change of the polymer and the temperature distribution in the die have been evaluated. The results show that the temperature of the region close to the pelletizing surface is relatively low due to the cooling effect of the cool water, while the temperature deeper inside the die is higher, with a lower temperature gradient, as a result of the heating effect of the hot thermal oil and the polymer. A solidification phase change of the polymer occurs near the polymer outlet due to heat loss from the polymer to the water, while deeper inside the hole the polymer remains fluid without solidification, due to heating by the thermal oil. Numerical simulation provides a reliable method to optimize the design of the die, the choice of metallic material for the die, and the operating conditions of the polymer pelletizing under water.

scholarly journals Experimental Investigation on Thermal Performance of Double-U-tube Heat Exchanger Using CuO/water Nanofluid as Heat Transfer Fluid

2020 ◽  
Vol 165 ◽  
pp. 01022
Author(s):  
Ruiqing Du ◽  
Dandan Jiang ◽  
Yong Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Heat Transfer Fluid ◽  
Geothermal Heat ◽  
Tube Heat Exchanger ◽  
Heating And Cooling ◽  
Geothermal Heat Exchanger

By applying the shallow ground energy to supply building heating and cooling, the geothermal heat exchanger systems were considered as an energy-efficient building service system. In this study, the CuO/water nanofluid was employed as circuit fluids of the geothermal heat exchanger system, and the thermal performance of the heat exchanger was investigated. The results showed that the heat transfer process of CuO/water nanofluid became stable earlier than that water. Furthermore, the heat transfer rate of nanofluid was higher than that of water when the heat transfer process plateaued.

Two-Phase Heat Transfer in a Wall-Driven Cubical Heat Sink

2016 ◽  
Author(s):  
Majid Molki
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Heat Sink ◽  
Volume Fraction ◽  
Turbulent Heat Transfer ◽  
Liquid Volume ◽  
Turbulent Heat ◽  
Fluid Temperature ◽  
Complex Flow ◽  
Liquid Volume Fraction

Turbulent heat transfer for flow of water-air mixture driven by moving walls in a cubical heat sink is investigated. One wall is maintained at an elevated temperature, while the vertical walls are at a low temperature. The cubical enclosure functions as a heat sink using water-air mixture with no phase change. Different arrangements for wall motion are considered, which include 1 to 4 moving walls. As the number of moving walls increases, the flow and heat transfer become more complex. In general, the flow reveals complex and multi-scale structures with an unsteady and evolving nature. The larger structure of the flow is resolved using Large Eddy Simulation, while the sub-grid scales are captured by the dynamic k-equation eddy-viscosity model. The focus of this work is on thermal field and heat transfer as affected by the complex flow field generated by multiple moving walls. The results indicate that the Nusselt number for the heat sink varies from 5202.8 to 7356.1, depending on the number of moving walls. Contours of fluid temperature, liquid volume fraction, local and average values of Nusselt number are among the results presented in this paper.

Simulation Study on Heat Transferring Performance of Vertical T-Tube Ground Heat Exchangers

2013 ◽  
Vol 805-806 ◽  
pp. 547-551
Author(s):  
Shao Wen Shang ◽  
Pei Pei Li ◽  
Dong Wen Fang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Common Ground ◽  
Inlet Temperature ◽  
Ground Heat Exchanger ◽  
Pump System ◽  
Heat Pump System ◽  
Tube Heat Exchanger ◽  
Ground Heat Exchangers ◽  
Ground Source

In the Ground Source Heat Pump system, the vertical U-tube is the most common ground heat exchanger. The heat transfer between the U-tube and the soil is affected by many factors. For analyzing the influence of these factors on heat transfer of the U-tube, I use GAMBIT software to establish a physical model who is used to simulated the heat exchanging of single U-tube heat exchanger and the surrounding soil physical. and mesh it. On the base, we take advantage of FLUENT software to make numerical simulation. After finishing analysis, we got some conclusions as follows: Under different tube wells depths and different inlet water temperature conditions, with the pipe inlet velocity increases, the heat exchanger performance improves, but the temperature difference between the import and the export will decreases. In addition to improve the inlet temperature of the U-tube, we can significantly increase the transferring heat of the ground heat exchanger.

CFD Investigation of Hydrodynamic and Heat Transfer Phenomena around Trilobe Particles in Hydrocracking Reactor

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammad Reza Bandari ◽  
Yaghoub Behjat ◽  
Shahrokh Shahhosseini
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Liquid Film ◽  
Transfer Coefficient ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Film Formation ◽  
Liquid Volume ◽  
Liquid Volume Fraction

In this work, computational fluid dynamics (CFD) has been employed to compute local convection heat transfer coefficient (h) that is the key parameter in calculation of heat transfer rate between the particle and fluids in packed bed reactors. In addition, the relation between Reynolds number and Nusselt number for spherical and trilobe catalyst particles have been investigated. Moreover, the parameters of Ranz-Marshall (R-M) correlation have been estimated in order to use it for trilobe catalyst particle. The heat transfer coefficients of the spherical and trilobe particles were compared and the effect of particle shape and configuration on heat transfer rate has been investigated. Eulerian-Eulerian approach was employed in order to investigate gas-liquid hydrodynamic especially liquid film formation around trilobe particles. The effects of liquid film around a trilobe particle and liquid volume fraction on heat transfer coefficient have also been studied. The CFD simulation results indicate that increasing inlet liquid volume fraction raises the liquid film thickness around the particles leading to reduction of heat transfer coefficient. In addition, the results revealed that flow field and temperature profiles around the particles became more complicated as a result of liquid film formation and gas-liquid interactions.

Effectiveness of a shell and helically coiled tube heat exchanger operated with gold nanofluids at low concentration: A multi-level factorial analysis

2020 ◽  
pp. 1-39
Author(s):  
Marina B. Fogaça ◽  
Daniele Toniolo Dias ◽  
Sergio L. Gómez ◽  
Jhon Jairo Ramirez Behainne ◽  
Rozane de Fátima Turchiello
Keyword(s):  
Heat Transfer ◽  
Gold Nanoparticles ◽  
Heat Exchanger ◽  
Volumetric Flow Rate ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Coiled Tube ◽  
Tube Heat Exchanger ◽  
Helically Coiled Tube ◽  
Multi Level

Abstract This work assesses the thermal performance of gold nanofluids as cooling liquid in a shell and helically coiled tube (SHCT) heat exchanger built in bench-scale. Tests planned under a multi-level factorial experimental design were carried out to evaluate the effects caused by the volumetric fraction of the gold nanoparticles, the volumetric flow rate of the working fluid and the inlet temperature of the hot fluid (water) on the SHCT heat exchanger effectiveness. Spherical gold nanoparticles with mean diameter of 14±2 nm were produced from the Turkevich's method to be used in two concentrations of about 10-5 %vol. The heat transfer tests were performed at volumetric flow rates of 20, 30 and 40 L/h for both working fluids using heated water at inlet temperatures of 40, 50 and 60°C. Results showed that the less concentrated nanofluid was comparatively more efficient, suggesting the presence of a range of values of the gold concentration for the existence of an improvement on the effectiveness in the heat transfer.

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