Finite element model for thermal analysis of ceramic heat exchanger tube under axial non-uniform convective heat transfer coefficient

2004 ◽  
Vol 25 (6) ◽  
pp. 479-482 ◽  
Author(s):  
Yasar Islamoglu
2014 ◽  
Vol 925 ◽  
pp. 625-629 ◽  
Author(s):  
C.S. Oon ◽  
A. Badarudin ◽  
S.N. Kazi ◽  
M. Fadhli

The heat transfer in annular heat exchanger with titanium oxide of 1.0 volume % concentration as the medium of heat exchanger is considered in this study. The heat transfer simulation of the flow is performed by using Computational Fluid Dynamics package, Ansys Fluent. The heat transfer coefficients of water to titanium oxide nanofluid flowing in a horizontal counter-flow heat exchanger under turbulent flow conditions are investigated. The results show that the convective heat transfer coefficient of the nanofluid is slightly higher than that of the base fluid by several percents. The heat transfer coefficient increases with the increase of the mass flow rate of hot water and also the nanofluid.


Author(s):  
S. V. Sridhar ◽  
R. Karuppasamy ◽  
G. D. Sivakumar

Abstract In this investigation, the performance of the shell and tube heat exchanger operated with tin nanoparticles-water (SnO2-W) and silver nanoparticles-water (Ag-W) nanofluids was experimentally analyzed. SnO2-W and Ag-W nanofluids were prepared without any surface medication of nanoparticles. The effects of volume concentrations of nanoparticles on thermal conductivity, viscosity, heat transfer coefficient, fiction factor, Nusselt number, and pressure drop were analyzed. The results showed that thermal conductivity of nanofluids increased by 29% and 39% while adding 0.1 wt% of SnO2 and Ag nanoparticles, respectively, due to the unique intrinsic property of the nanoparticles. Further, the convective heat transfer coefficient was enhanced because of improvement of thermal conductivity of the two phase mixture and friction factor increased due to the increases of viscosity and density of nanofluids. Moreover, Ag nanofluid showed superior pressure drop compared to SnO2 nanofluid owing to the improvement of thermophysical properties of nanofluid.


2014 ◽  
Vol 644-650 ◽  
pp. 459-462
Author(s):  
Yao Ye ◽  
Feng Wang ◽  
Yong Hai Wu

The temperature field of cylinder liner directly affects the working process of the engine cylinder. Its research is an important research direction of the engine research. We analysis the location relationship between the cylinder liner and cooperate with the components analysis in this paper. Then the finite element model of cylinder liner component is established and boundary conditions such as gas convective heat transfer coefficient, the piston top heat transfer coefficient are analyzed. A certain type of engine cylinder liner is calculated by using ANSYS temperature field equation solvers. The model and the calculation method this article uses are of great significance for the temperature field research of other heat transfer components.


2018 ◽  
Vol 13 (1) ◽  
pp. 71-76
Author(s):  
Vasyl Zhelykh ◽  
Olena Savchenko ◽  
Vadym Matusevych

Abstract To save traditional energy sources in mechanical ventilation systems, it is advisable to use low-energy ground energy for preheating or cooling the outside air. Heat exchange between ground and outside air occurs in ground heat exchangers. Many factors influence the process of heat transfer between air in the heat exchanger and the ground, in particular geological and climatic parameters of the construction site, parameters of the ventilation air in the projected house, physical and geometric parameters of the heat exchanger tube. Part of the parameters when designing a ventilation system with earth-air heat exchangers couldn’t be changed. The one of the factors, the change which directly affects the process of heat transfer between ground and air, is convective heat transfer coefficient from the internal surface of the heat exchanger tube. In this article the designs of a horizontal earthair heat exchanger with heat pipes was proposed. The use of heat pipes in designs of a horizontal heat exchanger allows intensification of the process of heat exchange by turbulence of air flow inside the heat exchanger. Besides this, additionally heat transfer from the ground to the air is carried out at the expense of heat transfer in the heat pipe itself.


2021 ◽  
Vol 7 (1) ◽  
pp. 279-287
Author(s):  
Z. Guo ◽  
J. Shan ◽  
J. Li ◽  
A. Levtsev

Pulse enhanced heat transfer technology is introduced, and a plate heat exchanger is designed. A pulsating valve is installed at the outlet of the heat exchanger to pulsate the heat medium. Pulsating and non-pulsating heat transfer tests are carried out on the same heat exchanger. On the basis of experiments, the effective temperature difference, heat flow and convective heat transfer coefficient of the heat exchanger at different pulse frequencies are analyzed by combining the theory of pulse enhanced heat transfer technology, heat transfer capacity, heat flow and convective heat transfer coefficient. Find the relationship between pulsation frequency of heat transfer effect of heat exchanger. The experimental results show that the heat exchanger has high heat transfer efficiency under the experimental conditions when there is pulsation.


Author(s):  
Z M Hu ◽  
J W Brooks ◽  
T A Dean

An investigation of die temperature changes and the heat transfer coefficient during hot forging of titanium alloy has been carried out using experiments and a thermal-plastic coupled finite element analysis. Hot Ti-6A1–4V rings were forged between two heated flat dies made of Inconel alloy IN718. The bottom die was instrumented with high-response thermocouples on its surface and subsurface. The recorded temperatures were analysed and used to determine the interface heat transfer coefficient between the die and the workpiece in conjunction with the thermal-plastic coupled finite element analysis using a reverse algorithm. The coefficients determined were then used in a finite element model for the analysis of the upsetting process and the results produced were in good agreement with the experimental data.


2013 ◽  
Vol 312 ◽  
pp. 445-449
Author(s):  
Yu Su

This paper develops a 2D finite element model for the enhanced cooling cutting of stainless steel. The enhanced cooling effect is modeled with a convective heat transfer coefficient assigned to a heat transfer window of cutting zone. Five convective heat transfer coefficients are defined to simulate different enhanced cooling effects. The simulation results suggest that increase of convective heat transfer coefficient results in a very small reduction of maximum tool-chip interface temperature, even when a very large convective heat transfer coefficient is used. In addition, no significant effect on cutting force and thrust force is observed with the increase of convective heat transfer coefficient.


2015 ◽  
Vol 752-753 ◽  
pp. 458-465
Author(s):  
P.C. Sreekumar ◽  
K. Krishnamoorthy ◽  
R. Ratheesh

Heat transfer augmentation techniques ultimately results in the reduction of thermal resistance in a conventional heat exchanger by generating higher convective heat transfer coefficient. Present study with the use of Alumina (Al2O3)/water nanofluid and baffled twisted tape inserts in double pipe heat exchanger as compound augmentation technique. Experiments were conducted to evaluate the heat transfer coefficient and friction factor for the flow through the inner tube of heat exchanger in turbulent flow range (8000<Re<60000). The effect of rectangular, circular, triangular baffled twisted tape having twist ratio (y/w) 4.2 and twisted tapes without baffles of twist ratio (y/w) 4.2 and 5.2 were studied. Experiments were conducted for both water and 0.1% volume concentration Alumina/water nanofluid. It is found that the enhancement of heat transfer coefficient by using rectangular baffled twisted tape and nanofluid is about 20%. Performance evaluation criteria were found for water and nanofluid and it was observed that rectangular baffled twisted tape performs better than other twisted tapes.


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