ESTIMATION OF FIXED BED HEAT TRANSFER PARAMETERS WITH ORTHOGONAL COLLOCATION

【摘要】 <正> Two heat transfer parameters in the fixed bed,radial effective conductiviw k_er,and wall heat transfer coefficient h_ware estimated by using the method of orthogonal collocation and non-linear least square.The temperatures at forty collo-cation points distributed along the radial direction are measured simultaneously by means of multiehannel data logger.Theeffects of bed height,Re_p,d_t/d_p,gas inlet temperature and wall temperature on k_erand h_w are studied.The results indicatethat the effect of gas inlet temperature and wall temperature is negligible.Bed height will only influence the parameter es-timations in shallow bed and at low Re_p.Both k_erand h_w tend to reach a limit with increasing bed height.The asymptoticbed height which is independent of d_p is about 0.5 m,while the asymptotic values of k_erand h_w increase with d_p.The pa-rameters obtained with the wall being heated are about 10% lower than those with the wall being cooled.k_er,h_w and stag-nant contribution terms k_erand h_w are all related to dp·k_erand h_w estimated at the asymptotic bed height are correlated bythe following equations:k_er=0.199+0.015 d_t/d_p+0.0020/（1+14.15（d_p/d_t）²）Re_ph_w=33.4+4.23d_t/d_p+0.333/（1+8.54（d_p/d_t）²）Re_p（5.5<d_t/d_p<13）（100<Re_p<500）更多还原

【Abstract】 Two heat transfer parameters in the fixed bed,radial effective conductiviw k_er,and wall heat transfer coefficient h_w are estimated by using the method of orthogonal collocation and non-linear least square.The temperatures at forty collo- cation points distributed along the radial direction are measured simultaneously by means of multiehannel data logger.The effects of bed height,Re_p,d_t/d_p,gas inlet temperature and wall temperature on k_erand h_w are studied.The results indicate that the effect of gas inlet temperature and wall temperature is negligible.Bed height will only influence the parameter es- timations in shallow bed and at low Re_p.Both k_erand h_w tend to reach a limit with increasing bed height.The asymptotic bed height which is independent of d_p is about 0.5 m,while the asymptotic values of k_erand h_w increase with d_p.The pa- rameters obtained with the wall being heated are about 10% lower than those with the wall being cooled.k_er,h_w and stag- nant contribution terms k_erand h_w are all related to dp·k_erand h_w estimated at the asymptotic bed height are correlated by the following equations: k_er=0.199+0.015 d_t/d_p+0.0020/（1+14.15（d_p/d_t）²）Re_p h_w=33.4+4.23d_t/d_p+0.333/（1+8.54（d_p/d_t）²）Re_p （5.5<d_t/d_p<13）（100<Re_p<500）更多还原