Tu Shan-Tung

Numerical and Experimental Study on the Heat Transfer and Pressure Drop of Compact Cross-Corrugated Recuperators

Recuperator is one of the key components in high temperature gas cooled reactors. Although cross-corrugated plates have been used to increase the thermal performance of the recuperators, the fundamental mechanisms of fluid flow and heat transfer are generally not clear. Fluid dynamics simulations and experiments are hence carried out to study the performance of the recuperators. A periodic cell is employed as the control volume. The flow field and heat transfer in sine-wave crossed-corrugated channels are investigated based on the Navier–Stokes and energy equations in the laminar flow regime between Re = 84 and 1168. The numerical results of the heat transfer factors and friction factors in different operating conditions show a fairly good agreement with the experimental measurements. The influence factors on the heat transfer and the hydraulic performance are also discussed in the paper. It is found that the heat transfer factor j and friction factor f decrease with the increase of the pitch-height ratio for a given Reynolds number.

Comparison of heat transfer and pressure drop in different recuperator geometries with corrugated walls

Recuperator is one of the key devices in the high temperature gas turbine system, which is mandatory to achieve 30% electrical efficiency or higher for microturbine engines. Cross-corrugated recuperators provide high heat transfer capabilities with compact size, light weight and strong mechanical strength. Flow in such geometries is usually laminar with typical Reynolds numbers varying from 300-2000. In order to understand mechanisms of flowing and heat transfer, periodic fully developed fluid flow and heat transfer in three types of cross-corrugated structures with inclination angle at 90o are investigated numerically. Periodicity is used to reduce the complexity of the channel geometry and enables the smallest possible segment of the flow channel to be modeled. The velocity and temperature distributions are obtained in the three-dimensional complex domain. Besides a detailed flow analysis, comparison of the local heat and mass transfer and the pressure losses for these geometries are presented. It is shown that the flow phenomena caused by the different geometries are of significant influence on the homogeneity and on the quantity of the local heat and mass transfer as well as on the pressure drop.