화학공학소재연구정보센터
Canadian Journal of Chemical Engineering, Vol.94, No.1, 134-141, 2016
Investigation of Impingement Heat Transfer for Air-Sand Mixture Flow
Heat transfer between a heated flat plate and normal impinging gas-solid two-phase jet flow was investigated. A single jet from a nozzle of 10 mm diameter at nozzle-to-plate distance/nozzle diameter ratio in the range of 2-8 was used. Natural sand particles with average diameters of 220, 350, and 550 mu m were used as a solid phase. The effects of particle size and loading ratio (mass of sand/mass of air) at different jet velocities on impingement cooling characteristics of the flat plate are investigated. The numerical simulations were performed with ANSYS Fluent 14.7 for a steady, three-dimensional, incompressible turbulent flow using Eulerian simulation for the gas phase and Lagrangian simulation for sand particles. The experimental results show that the existence of sand particles decreases the Nusselt number compared to air jet flow. The single and two-phase flow experimental results are close to predictions when the particle reflection option is used in the simulation. The discrepancy in local values near the stagnation point can be attributed to the complex nature of the two-phase flow at the stagnation point that includes reflection of sand particles at different angles.