Number：

05_01鄭澤明

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Name：

Tzer-Ming Jeng

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Heat transfer characteristics of a rotating cylinder with a lateral impinging air jet

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Keywords：Rotating cylinder Lateral impinging jet Heat transfer Experiment

Abstract：This study experimentally investigated the heat transfer characteristics of a rotating cylinder under lat-eral air impinging jet.The height and diameter of the cylinder were fixed,and the variable parameters were as follows(1)the jet Reynolds number(Rej=655.60237);(2)the rotational Reynolds number(Rer=1975-7899);(3)the ratio of the cylinder diameter(D)to the nozzle width(w)(D/w=2-16);(4)the relative jet-impinging distance(L/w=1-16,L is the shortest nozzle-to-cylinder).This exper-iment measured detailed temperature on the heated wall surface of the cylinder using an infrared thermo tracer,and observed the smoke flow characteristics of the stationary and rotating cylinder under imping-ing jet flow using visualization technique.The experimental results showed that the rotation changed the separation position of impinging jet flow on the cylinder,and allowed the surface temperature of the cyl-inder to tend towards uniformity along the circuferential direction of the cylinder.In addition,the heat transfer experiment included the pure rotating condition,the pure jet-flow condition and the coexistent condition of rotation and jet flow.The results showed that the average Nusselt number(Nu)increased with the increase of Re,and Rer,and decreased with the increase of D/w.The influence of D/w on Nu decreased with the increase of L/w,and Nu first increased and then decreased with the increase of L/w.In other words,there is a critical L/w value that can produce the highest Nu,and the critical L/w value

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