Study on improvement of effective heat transfer temperature difference and enhancement of compound heat transfer in laminar flow

Effective heat-transfer temperature difference(EHTD) was applied in the investigation of the heat-transfer enhancement theory with laminar flow in heat exchanger.Investigation was performed on the phenomenon,details and the law of EHTD,which reveals the intrinsic mechanism of laminar heat transfer enhancement with inserts.The suitable utilization method of the slowly varying characteristic of EHTD was discussed,and the optimization approach to improve EHTD was put forward.Collaborative heat-transfer enhancement mechanism for rough rib surface with inserts in heat-transfer channels was analyzed,which reveals the effect and law of EHTD improved by the rough rib surface in laminar flow.