EXPERIMENTAL STUDY OF NATURAL CONVECTION HEAT TRANSFER COEFFICIENT FROM FLAT ASBESTOSE-CEMENT

	EXPERIMENTAL STUDY OF NATURAL CONVECTION HEAT TRANSFER COEFFICIENT FROM FLAT ASBESTOSE-CEMENT
AL-TAQANI
Article 1, Volume 24, Issue 8, 2011, Pages 0-0
Abstract
Natural convection heat transfer from flat asbestose – cement sheet which used in roofing and building constructions was studied experimentally. With air as the working fluid , the effects of heat flux and inclination angle on the local and average heat transfer coefficients were examined . The asbestos cement (0.45 * 0.45m) which heated surface facing upwards , was subjected to constant heat flux at arrange (1111 , 607 , 252 , 87 W/m2) and the experimental study was done with a range of inclination angles (00 , 150 , 300 , 450 ) from vertical . Results show that the local heat transfer coefficient increase with increasing of heat level or increasing the angle of inclination , Radiation heat transfer take place at (55 – 93%) percent from heat flux which provided to asbestose – cement sheet and convection heat transfer at (45 – 4.59%) percent . The relation between local Nusselt number and local Rayliah number which obtained from experimental results is : Nux = 1.34 (Rax)0.179 1 * 108 < Rax < 3 * 108
Keywords
Natural Convection; Flat sheet; Asbestose; Cement

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