http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nares Chimres,Thunyawat Chittiphalungsri,Lazarus Godson Asirvatham,Ahmet Selim Dalkılıç,Omid Mahian,Somchai Wongwises 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.10
The air side thermal performance of wavy fins with rectangular winglets are studied using experimental and numerical methods. The following parameters are selected for investigation: the attack angle, placed location, span and length of the rectangular winglet. The results show that all parameters affect the thermal performance of the air side. The best configurations of the winglet that provide the maximum j/f (1/3) for both winglet lengths are the 3.5 mm horizontal distance, 7 mm vertical distance, 60 o attack angle and 1.25 mm winglet span. Moreover, the thermal performance comparisons between the optimal design of the wavy fin with winglet and normal wavy fin are reported. Wavy fins with winglets provide a larger heat transfer coefficient, pressure drop and j/f (1/3) than those of normal wavy fins. For the j/f (1/3)comparison, wavy fins with winglets provide a j/f (1/3) greater than that of normal wavy fins by 5.4-14.6 %, with the Reynolds number ranging from 1650 to 4423.
Experimental Investigation on the Performance of a Parallel Plate-Based Active Magnetic Regenerator
Thawatchai Keawkamrop,Ahmet Selim Dalkilic,Lazarus Godson Asirvatham,Jafar Amani,Omid Mahian,Somchai Wongwises 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.2
This paper describes a prototype of a linear reciprocating magnetic refrigerator using a gadolinium parallel plate. The new design of the regenerator, installation, and experiment is presented. The regenerator consists of a gadolinium plate and an inlet/outlet section. The thickness and length of the gadolinium plate are 1mm and 80mm, respectively. The gap between parallel plates is 0.1mm. Water is used as the heat transfer °uid. The permanent magnet structure used in the present study can generate a maximum magnetic ¯eld intensity of 0.94 T. The effects of surface roughness of the gadolinium parallel plate on the temperature span and cooling capacity are investigated. The results show that there is no signi¯cant effect of surface roughness on the magnetic refrigerator performance at a high utilization factor. The results from the present study are important for the design of magnetic refrigerators operating at room temperature.
Aldin Justin Sundararaj,B.C. Pillai,Lazarus Godson Asirvatham 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4
A detailed experimental study of the fuel flow characteristic and the convective heat transfer of a nano fluid consisting of refined kerosene have been studied in the present work. Low volume fraction of 0.01 and 0.05 of Al 2 O 3 - refined kerosene has been studied. A horizontal tube of 4 mm in diameter was used for the fluid flow and the heat flow under various Reynolds number ranging from 500 to 5500 were investigated. SEM analysis showed particle size of alumina nanoparticle ranged from 32 nm – 50 nm. It was found that, higher the volume fraction of the refined kerosene- Al 2 O 3 nano fluid, larger is the heat transfer coefficient. Moreover it was found that with increase in volume fraction of nano particles in the fluid, the nano fluid’s viscosity also increased which results in an increase in friction factor. The friction factor and pumping power were also investigated under various Reynolds number and volume fraction. An increase of 16.33 % in convective heat transfer was observed at Reynolds number of 5500 for a volume fraction of 0.05 %. All results provide strong proof that the addition of nanoparticles intensified the above properties to a considerable rate.
Thermal performance of a vapor chamber for electronic cooling applications
Jefferson Raja Bose,Nizar Ahammed,Lazarus Godson Asirvatham 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4
The heat transfer performance of a vapor chamber and its effectiveness in the cooling of electronic devices are experimentally and theoretically investigated in the present work. The power transistor in the circuit board usually operates with electric power that ranges from 15 W to 100 W, which is the heat input to the simulated processor. The heat flux varies between 3300 and 22000 W/m 2 . The simulated processor is cooled with the forced and induced air cooling methods with and without the use of the vapor chamber. Results show a maximum temperature decrease of 26 % and a maximum increase in the convective heat transfer coefficient of 36 %. The minimum value of the thermal resistance through the vapor chamber and the total thermal resistance is 0.195 and 0.82 °C/W, respectively. The experimental results are compared with the ANSYS predicted values.