scholarly journals An Inverse Problem of Temperature Optimization in Hyperthermia by Controlling the Overall Heat Transfer Coefficient

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Seyed Ali Aghayan ◽  
Dariush Sardari ◽  
Seyed Rabii Mahdi Mahdavi ◽  
Mohammad Hasan Zahmatkesh
Keyword(s):  
Heat Transfer ◽  
Inverse Problem ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling System ◽  
Adjoint Equation ◽  
Bioheat Transfer ◽  
Tissue Temperature ◽  
Hyperthermia Treatment ◽  
Overall Heat Transfer Coefficient

A novel scheme to obtain the optimum tissue heating condition during hyperthermia treatment is proposed. To do this, the effect of the controllable overall heat transfer coefficient of the cooling system is investigated. An inverse problem by a conjugated gradient with adjoint equation is used in our model. We apply the finite difference time domain method to numerically solve the tissue temperature distribution using Pennes bioheat transfer equation. In order to provide a quantitative measurement of errors, convergence history of the method and root mean square of errors are also calculated. The effects of heat convection coefficient of water and thermal conductivity of casing layer on the control parameter are also discussed separately.

scholarly journals Mini Channel Evaporator as MAC Device for Laptop Cooling System

2020 ◽  
Vol 8 (5) ◽  
pp. 2993-2998
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Air Conditioning ◽  
Cooling System ◽  
Laptop Computer ◽  
Air Conditioning System ◽  
Overall Heat Transfer Coefficient ◽  
Flow Through ◽  
Cooling Methods

Laptop computers are known for their compact features which lead to overheating problems. Along with its being compact, laptop computer developers are going for more advance components to be able to run advance computer programs making the laptop do much more which also adds more to the overheating problems of the laptop. Overheated laptops will lead to slower laptop performances, laptop failures and even damaging its components. This problem leads to the development of laptop cooling methods, from fans and blowers and other cooling methods. This study aims to develop a cooling system which involves an air-conditioning system, a Mini Air Conditioning System (MAC System). The key to this study is the fabrication of three(3) mini channel evaporators which has different inner hydraulic diameters but of the same surface area with an overall size and which is smaller than a laptop battery pack. The evaporator for this study was made from a copper block that was fabricated to produce fins and a groove for the refrigerant to flow through the evaporator. The inner hydraulic diameters for the refrigerant to flow through are, 1mm, 2mm, and 3mm. The overall heat transfer coefficient would be determined for each evaporator size. The study showed that the most effective evaporator for cooling the laptop was that of the 3mm evaporator and that using the MAC system is an effective way of cooling a laptop computer. It lowered the temperature of the laptop by 10.65 K versus the setup with no cooler at all and 8.01 K with the setup with a plain cooler. The study also showed that the 3mm evaporator has the highest overall heat transfer coefficient with 73.129W/m2K with a mass flow rate of 0.039 kg/s.

scholarly journals Estimation of overall heat transfer coefficient of cooling system in RF capacitive hyperthermia

2013 ◽  
Vol 06 (05) ◽  
pp. 509-517 ◽  
Author(s):  
Seyed Ali Aghayan ◽  
Dariush Sardari ◽  
Seyed Rabii Mahdi Mahdavi ◽  
Mohammad Hasan Zahmatkesh
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling System ◽  
Overall Heat Transfer Coefficient

scholarly journals A numerical model and validation of phase change material integrated thermoelectric radiant cooling panel

2019 ◽  
Vol 111 ◽  
pp. 01001
Author(s):  
Hansol Lim ◽  
Hye-Jin Cho ◽  
Seong-Yong Cheon ◽  
Soo-Jin Lee ◽  
Jae-Weon Jeong
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Model ◽  
Surface Temperature ◽  
Phase Change ◽  
Transfer Coefficient ◽  
Phase Change Material ◽  
Overall Heat Transfer Coefficient ◽  
Radiant Cooling ◽  
Change Material

A phase change material based radiant cooling panel with thermoelectric module (PCM-TERCP) is proposed in this study. It consists of two aluminium panels, and phase change materials (PCMs) sandwiched between the two panels. Thermoelectric modules (TEMs) are attached to one of the aluminium panels, and heat sinks are attached to the top side of TEMs. PCM-TERCP is a thermal energy storage concept equipment, in which TEMs freeze the PCM during the night whose melting temperature is 16○C. Therefore, the radiant cooling panel can maintain a surface temperature of 16◦C without the operation of TEM during the day. Furthermore, it is necessary to design the PCM-TERCP in a way that it can maintain the panel surface temperature during the targeted operating time. Therefore, the numerical model was developed using finite difference method to evaluate the thermal behaviour of PCM-TERCP. Experiments were also conducted to validate the performance of the developed model. Using the developed model, the possible operation time was investigated to determine the overall heat transfer coefficient required between radiant cooling panel and TEM. Consequently, the results showed that a overall heat transfer coefficient of 394 W/m2K is required to maintain the surface temperature between 16○C to 18○C for a 3 hours operation.

The Effect of Baffles in Shell and Tube Heat Exchangers

2009 ◽  
Vol 62-64 ◽  
pp. 694-699 ◽  
Author(s):  
E. Akpabio ◽  
I.O. Oboh ◽  
E.O. Aluyor
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Exchangers ◽  
Proper Position ◽  
Process Industries ◽  
Overall Heat Transfer Coefficient ◽  
Shell And Tube ◽  
Optimal Values ◽  
Side Flow

Shell and tube heat exchangers in their various construction modifications are probably the most widespread and commonly used basic heat exchanger configuration in the process industries. There are many modifications of the basic configuration which can be used to solve special problems. Baffles serve two functions: Most importantly, they support the tubes in the proper position during assembly and operation and prevent vibration of the tubes caused by flow-induced eddies, and secondly, they guide the shell-side flow back and forth across the tube field, increasing the velocity and the heat transfer coefficient. The objective of this paper is to find the baffle spacing at fixed baffle cut that will give us the optimal values for the overall heat transfer coefficient. To do this Microsoft Excel 2003 package was employed. The results obtained from previous studies showed that to obtain optimal values for the overall heat transfer coefficient for the shell and tube heat exchangers a baffle cut of 20 to 25 percent of the diameter is common and the maximum spacing depends on how much support the tubes need. This was used to validate the results obtained from this study.

Energy Efficient Hybrid Nanofluids for Tubular Cooling Applications

2014 ◽  
Vol 592-594 ◽  
pp. 922-926 ◽  
Author(s):  
Devasenan Madhesh ◽  
S. Kalaiselvam
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Volume Concentration ◽  
Thermal Characteristics ◽  
Hybrid Nanofluid ◽  
Tubular Heat Exchanger ◽  
Overall Heat Transfer Coefficient ◽  
Flow Through ◽  
Hybrid Nanofluids

Analysis of heat transfer behaviour of hybrid nanofluid (HyNF) flow through the tubular heat exchanger was experimentally investigated. In this analysis the effects of thermal characteristics of forced convection, Nusselt number, Peclet number, and overall heat transfer coefficient were investigated.The nanofluid was prepared by dispersing the copper-titania hybrid nanocomposite (HyNC) in the water. The experiments were performed for various nanoparticle volume concentrations addition in the base fluid from the range of 0.1% to 1.0%. The experimental results show that the overall heat transfer coefficient was found to increases maximum by 30.4%, up to 0.7% volume concentration of HyNC.

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