NUMERICAL-ANALYSIS OF FLOW PATTERN OF IMPINGING LIQUID SPRAYS IN A COLD MODEL FOR COOLING A HOT FLAT-PLATE

This paper treats the numerical analysis of two-phase mist jet flow, which is commonly adopted to cool the solidified shell in the secondary cooling zone of the continuous casting process. Flow structures of the two-phase subsonicjet impinging on a flat plate normal to flow, corresponding to the present cooling situation, are solved on the assumption that particles are perfectly elastically reflected from a surface. Again, the numerical experiments concerning mist flows composed of air and water-droplets are made in a cold model. The flow fields for both gas and particle phases strongly depend upon the particle size. When water-droplets mixing in the mist are very small, the impinging particles travel very closely to the surface. With increasing particle size, particles are reflected from the surface in a far distance. Therefore, also, the case is analysed where a low velocity annular gas-only flow surrounding a round nozzle co-axially is present so that such idle particles may be pushed back to the surface again. This is considered to result in an improvement of the mist cooling efficiency.