Experiments were conducted to study the heat transfer characteristics of a rotating ribbed square serpentine passage for unsteady cases. Abundant experimental data were obtained to investigate the variation of heat transfer coefficient at different engine working conditions, such as mass flux and rotational speed. For unsteady cases, the convective heat transfer was affected by the cross-stream secondary flow caused by unbalance distribution of the Corilis, the buoyancy and the angular acceleration forces. Effects of angular acceleration force increase heat transfer coefficients on leading surface and decrease the coefficients on trailing surface in radial outward passage flow for the accelerating rotation system; Reverse conclusions can be obtained for the case of decelerated rotation system. It is shown that the fluctuations of heat transfer coefficients occur mainly at the moment when the work conditions vary under unsteady cases. The fluctuations of heat transfer coefficients mainly occur at the moment when the work conditions change, though long exists of the walls temperatures variation. An interesting phenomenon was also observed that there exists a hysteresis of Nu number ratio when the variation of rotational speed completes a cycle.
Deng Hongwu, Tao Zhi, Xu Guoqiang, Ding Shuiting.Experiment of heat transfer within a rotating ribbed serpentine passage in unsteady cases[J] JOURNAL OF BEIJING UNIVERSITY OF AERONAUTICS AND A, 2005,V31(09): 1004-1008
Morris T, Fukada W, Nakayama.null Convective heat transfer in a rotating radial circular pipe (2nd report)[J]. Int J Heat Mass Transfer.1971,14:1807-
Chang S W, Morris W D.null Heat transfer in a radially rotating square duct fitted with in-line transverse ribs[J]. International Journal of Thermal Sciences.2003,42:267-
�˺���,�� �,�� ��.��ת״̬�´���U��ͨ���ڻ��ȵ�ʵ���о�[J] ������,2000,21(1):26~29 Deng Hongwu, Zhang Wei, Tao Zhi. Experimental investigation on heat transfer within a rotating ribbed serpentine passage [J] Joural of Propulsion Technology, 2000, 21(1):26~29(in Chinese)
�˺���.�Ƕ���״̬����ת����ͨ���������������뻻�������о� .����:�������պ����ѧ Դ�붯������ѧԺ ,2002 Deng Hongwu. Flow and heat transfer characteristics of coolant through a rotating serpentine passage in unsteady cases . Beijing:Collage of Energy and Power Engineering, Beijing University of Aeronautics and Astronautics, 2002(in Chinese)