Jet Entrainment Rates of Air Curtain to Open-Type Refrigeration Display Cabinet Efficiency

• Main Authors: Jin-Tang Li, 李金堂
• Other Authors: R. Tsai
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/73098927048592279751

碩士 === 中原大學 === 機械工程研究所 === 96 === ABSTRACT The present work is to discuss the discharge of flow velocity, turbulent intensity, discharging angles and back panel flow inlet to sustain the efficiency of air curtain and reduce the temperature gradient of the cabinet. We set the flow inlet velocity in a range of to research the influence of air curtain efficiency and select several suitable parameter of velocity to test the entrainment rate. We discuss the correlation among the discharging velocity of , turbulence intensity of 5~25％ and discharging angles of -20°~20° accompanied with whether the back panel flow inlet is existing or not. The commercial code of CFDRC is adopted to simulate and the results depict the velocity and temperature distributions. After simulation and analysis, we can figure that the optimum velocities are in a range of and the entrainment rate can be decreased by the weaker turbulence intensity efficiently. The optimum discharging angle is between 15°and 20° which the flow could be linked to the return air grill and decrease the entrainment rate. In other respects, to compare the results of opening the level of 5 and 6, it could be seen the cooling effects on both A and B sections and the temperature decrease is about 2~3K. The temperature would increase if the level of 5or 6 is not opening. The cooling performance is not so obviously on section A, whereas the temperature decrease is about 3K on section B, thus a lot of free space could be released.