Numerical investigation on heat transfer characteristics of the plate air heater with variable channels and experimental validation

This paper presents a novel plate air heater using steam as the high temperature fluid. The heat transfer characteristics of the air heater were numerical simulated in different steam and air volume flow rates with Fluent and a user-defined function (UDF) as well as verification by experiment. The results showed the variable channel structure of the new plate air heater promptly condensed liquid discharge, reduced the thickness of the steam film and improved the speed of condensing steam. In this experimental model, when the temperature of the steam side reached 120 °C, the flow rate was 12 m3 ⋅ h−1 and the air side flow was 480 m3 ⋅ h−1. The total heat transfer coefficient was approximately 70 W (m2 ⋅ K)−1 and the drop in pressure of the steam side was less than 1 kPa.