HEAT TRANSFER CHARACTERISTICS OF SCREEN MATRICES AT LOW REYNOLDS NUMBERS

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Authors
St. Ville, Edward L.
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Date of Issue
1959
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Monterey, California: U.S. Naval Postgraduate School
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en_US
Abstract
The convective heat transfer characteristics of six screen matrices with a range of porosity from 0.602 to 0.832 are presented. The characteristics were investigated over a Reynolds number range of 0.1 to 10, based on hydraulic diameter. The data was obtained by passing air through a 6 in. diameter woven screen matrix composed of three stacked screens. The heat transfer data was obtained by use of the transient technique developed by G. L. Locke at Stanford University. Temperature-time history of the downstream air temperature is used to determine the maxi mum slope of the experimental cooling curve. From a plot of maximum slope versus NTU of the generalized cooling curve, which is a unique solution for this type of cooling, an evaluation of the experimental NTU is possible. With the NTU thus determined, the experimental value of the thermal conductance coefficient, h, is readily obtained. The present data is an extension of existing data and was obtained using the same type of matrices but with a slightly different technique and over a lower range of Reynolds numbers. The present technique involves heating the screen matrix to a uniform temperature and introducing the screens into a stream of air entering at a uniformly lower temperature. The temperature-time history of the downstream air is recorded and available for analysis. Application of the present data is thought to be useful in transportation cooling of environmental chambers subjected to an external heat source.
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Mechanical Engineering
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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