Study on flow and heat transfer characteristics of trapezoidal heat transfer surface

A new type trapezoidal heat transfer surface was put forward, which can overcome the defect of the rectangular section duct. Besides, uniform temperature field distribution appeared in trapezoidal duct along the flow direction. The comparison of the heat transfer coefficients between trapezoidal and rectangular ducts at the same heat transfer area and flow conditions were performed in a standard setup. And the feasibility of the numerical simulation method was also testified by experimental results. Experimental and numerical data indicate that, when 1 300≤Re≤4 000, heat transfer coefficient of trapezoidal duct heat exchanger is better than that of rectangular duct. At a certain slope angle, with the increase of air flow, the distribution of temperature field is getting better and better, and the turbulence intensity in the rear of the duct is also enhanced. When 0≤β≤arctan(1/12), convective heat transfer intensity and pressure drop increase with the increasing of β, and the distribution of temperature field is more and more uniform. In order to evaluate the heat transfer and flow characteristic in the study, a DEC was brought. It can be seen that the overall heat transfer performance of trapezoidal heat transfer surface is better than that of rectangular heat transfer surface.