Abstract
For laminar and turbulent convective heat transfer, the synergy among vectorial physical quantities of a fluid particle is analyzed to reveal the relation between the multi-field synergy mechanism and heat transfer enhancement. Additionally, the efficiency evaluation criterion (EEC) is proposed to evaluate the overall performance of heat transfer enhancement. Meanwhile, using synergy angles α, β, θ, γ and η, a unified evaluation system and corresponding evaluation indexes for heat transfer enhancement are suggested. A model of a heat-transfer-enhanced tube inserted with poles in a triangular configuration is built, and a corresponding numerical simulation is conducted to verify the proposed evaluation system and criterion. The calculation results show that there is correlation between synergy angles reflecting the direction of heat transfer enhancement and evaluation criterion reflecting the effect of heat transfer enhancement. In the Re number range of 300–1800, the performance evaluation criterion PEC lies in the range of 1.2–2.3, but the efficiency evaluation criterion EEC lies in the range of 0.33–0.45.
Highlights
For laminar and turbulent convective heat transfer, the synergy among vectorial physical quantities of a fluid particle is analyzed to reveal the relation between the multi-field synergy mechanism and heat transfer enhancement
The problem is how to improve the comprehensive performance of a heat exchanger by reconciling heat resistance with flow resistance
Considering that the heat transfer can be related to distribution characteristics of the velocity field and temperature field, Guo et al proposed the field synergy principle of heat transfer enhancement
Summary
A problem we face in developing approaches to enhance heat transfer is that heat transfer is enhanced at the cost of an undesirable increase in flow resistance. Sometimes the energy saved by enhancing heat transfer may be less than the increase in energy cost due to flow resistance. An objective evaluation of the effect of heat transfer enhancement is necessary in designing high-efficiency and. Liu W, et al Chin Sci Bull May (2012) Vol.. No. low-resistance heat transfer units and exchangers Liu W, et al Chin Sci Bull May (2012) Vol. No.13 low-resistance heat transfer units and exchangers
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