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Abstract: By modifying the energy equation of finite volume of liquid flow, the viewpoint of heat conveyance is presented under the assumption of low velocity and viscosity. The factors of heat transfer are analyzed and the field synergy principle is extended. The forces related to the liquid in heat exchanger tubes with twisted-tape insert are analyzed and the influence on the flow field is indicated. With the consideration of the viewpoint of heat conveyance, the methods of reducing the floating resistance and increasing the efficiency of integrated heat transfer are presented. The distributing rules of liquid floating in the tube and heat transfer are obtained by numerical simulation
which shows that the slick tube has the highest integrated heat
transfer coefficient when the twisted-tape insert is about 500～600
mm. The analyses indicate that the length of the twisted-tape insert
has wider adjusting area to adapt to the actual work condition to obtained a higher heat transfer coefficient or to lower the floating resistance, and that a higher level of integrated heat transfer coefficient is still kept. The above analyses indicate that the viewpoint of heat conveyance could guide the design of new enhanced heat transfer structures.
Key words: Heat conveyance Enhanced heat transfer
Field synergy principle Twisted tape
Numerical simulation
CLC No: TK124
河南省杰出人才创新基金资助项目(0221000600). Received 20060613，received
in revised form
20061218
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