Shell-and-tube heat exchangers with helical baffles are now widely used in many engineering fields,especially in chemical and petroleum refining industries.The helical lead distance is one of the important design para...Shell-and-tube heat exchangers with helical baffles are now widely used in many engineering fields,especially in chemical and petroleum refining industries.The helical lead distance is one of the important design parameters.The continuous four-sector baffle was taken as an example,and the theoretical calculation method of the helical lead distance of the shell-and-tube heat exchanger with helical baffles was deduced.Then this procedure was extended to continuous n sectors baffle,continuous baffle and staggered sectors baffle.Finally,an equation to determine the helical lead distance for any kinds of helical baffle was proposed.A short discussion of the determination methods proposed in the literatures was presented.展开更多
Experimental investigation of heat transfer and flow resistance performance on heat exchanger with lozenge fin tubes supported by helical baffles was carried out. Under the experimental conditions,curves of relation b...Experimental investigation of heat transfer and flow resistance performance on heat exchanger with lozenge fin tubes supported by helical baffles was carried out. Under the experimental conditions,curves of relation between heat transfer film coefficient and flow velocity,relation between flow resistance coefficient and velocity were obtained,which provides references for industrial application of this type of heat exchanger. Experimental results indicated that within the range of diesel oil flow velocity 0.22-0.85 m·s -1,heat transfer film coefficient in shell side of heat exchanger with lozenge fin tubes supported by helical baffles was 512-1378?W·m -2·K -1,which was 54%-108% higher than that of heat exchanger with smooth tubes supported by helical baffles,while flow resistance coefficient was lower by 5%-30%,which showed that heat exchanger with lozenge fin tubes supported by helical baffles had favorable heat transfer and flow resistance performance.展开更多
文摘Shell-and-tube heat exchangers with helical baffles are now widely used in many engineering fields,especially in chemical and petroleum refining industries.The helical lead distance is one of the important design parameters.The continuous four-sector baffle was taken as an example,and the theoretical calculation method of the helical lead distance of the shell-and-tube heat exchanger with helical baffles was deduced.Then this procedure was extended to continuous n sectors baffle,continuous baffle and staggered sectors baffle.Finally,an equation to determine the helical lead distance for any kinds of helical baffle was proposed.A short discussion of the determination methods proposed in the literatures was presented.
文摘Experimental investigation of heat transfer and flow resistance performance on heat exchanger with lozenge fin tubes supported by helical baffles was carried out. Under the experimental conditions,curves of relation between heat transfer film coefficient and flow velocity,relation between flow resistance coefficient and velocity were obtained,which provides references for industrial application of this type of heat exchanger. Experimental results indicated that within the range of diesel oil flow velocity 0.22-0.85 m·s -1,heat transfer film coefficient in shell side of heat exchanger with lozenge fin tubes supported by helical baffles was 512-1378?W·m -2·K -1,which was 54%-108% higher than that of heat exchanger with smooth tubes supported by helical baffles,while flow resistance coefficient was lower by 5%-30%,which showed that heat exchanger with lozenge fin tubes supported by helical baffles had favorable heat transfer and flow resistance performance.
