碩士 / 國立臺北科技大學 / 冷凍與低溫科技研究所 / 90 / Abstract
A refrigerated semi-trailer plays a very important role in a cold chain. Its main function is to maintain perishable commodities in set conditions of temperature and humidity during the period of transport and delivery. With the progress of the standard of living, the request of refrigerated foods must increase year by year. In the other hand, Taiwan joins WTO in 2002 and imports diversified agricultural products from many countries. Therefore, the requirement of refrigerated semi-trailers must be increased day after day. However, keeping the quality of foods transported by a refrigerated semi-trailer is mainly affected by the uniformity of temperature, which depends on the airflow distribution. Hence, how to obtain even airflow distribution in a refrigerated semi-trailer is a very important issue.
First, this study builds a numerical model to simulate foods cooling process and investigates transient airflow fields, including velocity and temperature distribution in a refrigerated room. In the other hand, modeling accuracy is checked by experiment. It is founds that both simulation and experiment agrees well. Second, to find optimal airflow distribution, the developed model is used to predict the velocity and temperature distribution in a refrigerated semi-trailer, which is affected by different parameters, including return air dispose, air duct dispose, supplying air place and airflow rate dispose. This model considers the effect of radiation, turbulence and buoyancy.
It is found that at returning air place using buffer plate can get uniform temperature distribution, but this result can’t make perishable foods reach ATP request, therefore it must install internal air duct. According to the simulation results of different supply air place, it is found that air duct at 0,1/3 place has the best result, and temperature distribution is more uniform, but temperature drop rate is still slow. The simulating results of different supply air place and airflow rate reveal that air duct at 0,1/3,3/4 place and airflow rate 3:5:2 have a optimization. Using this design not only has uniform velocity and temperature distribution but also has good temperature control and foods quality.
| Identifer | oai:union.ndltd.org:TW/090TIT00703010 |
| Date | January 2002 |
| Creators | Yang Yung-Ming, 陽永明 |
| Contributors | 李宗興 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 102 |
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