In this paper, based on the traditional steam heating stirred tank, a new type tank is presented with low wall temperature and convex groove. The performance of heat transfer and fluid flow is studied using detached eddy model. The results show that the velocity near the rotor area is large. The velocity in static area is uniform. Due to the small interaction between the upper and down blades, there have four cycle vortex in the tank, which are two parallel vortexes near each blade. When the speed of impeller N=96 r/min, the wall temperature is 358 K to heating 293 K sugar water, the sugar water temperature could reach 337-340 K in 10 min, and it satisfies the need of techniques.