If the finned tube according to the convention can according to the type, in the practical range of heat transfer coefficient to determine the value of heat transfer coefficient. If these ranges are not met, the heat transfer area will be much larger than that required by the process. Otherwise, the power of conveying fluid needs to be increased. The heat transfer process in finned tube is not only the heat transfer phenomenon, but also the fluid flow state. It plays a controlling role in the heat transfer process. The heat transfer boundary layer on both sides of the heat transfer wall constitutes the main heat transfer horn. When the degree of turbulence increases, the boundary layer becomes thinner and the thermal resistance becomes smaller, which is beneficial to heat transfer. On the contrary, when the degree of turbulence decreases, it is unfavorable to heat transfer.
It is used for air precooling in air separation plant. The type and heat transfer rate of finned tubes should take into account the flow and heat value of recovered or transferred materials, the flow ratio and flow characteristics of finned tube fluids, the types of heat transfer wall materials, operating pressure and temperature variations, the continuity of operation, and in the nature of the fluids, in particular the degree of fouling of the fluids or whether they are suspensions, in these vicious cases. The importance of each element is different, but there is no difference in the importance of these factors in determining the type of finned tube.
In addition, the thickness of the wall should also be limited. The retrieved heat value, heat transfer area and finned tube price are inversely proportional to the frictional resistance of the fluid, thus affecting the cost of power remoteness. Generally, it is inconvenient to obtain reasonable and economical design and operation data after determining the type, but it is inconvenient to know the general norm of the most economical conditions before choosing the type. Therefore, the first step in juice design should be to give the approximate heat transfer coefficient and type, to find the rough heat transfer area of the mountain, and at the same time to study the most appropriate temperature difference. The ratio of the flow rate of the two fluids to the temperature difference.辛苦整理.转载请注明http://www.wxsxsjx.com
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