COLD MODEL EXPERIMENT FOR DEVELOPING A NE W VELOCIMETER APPLICABLE TOMOLTEN-METAL

The objective of this study is to develop a new velocimeter utilizing the drag force of a sphere which is applicable to velocity measurement of high temperature molten metal flow. Although the drag coefficient C(D) is required for the evaluation of drag force, has not been studie d for a fluid flow with high turbulence intensity and turbulence scale typical of ironmaking and steelmaking processes. Therefore, C(D) was measured using a sphere placed in a wind tunnel equipped with turbulen ce generator and correlated as a function of Reynolds number Re and tu rbulence intensity Tu. The effect of turbulence scale was found to be negligible. A new velocimeter using a sphere was developed and its app licability was examined in cold models such as an air jet of Tu is-app roximately-equal-to 2%, a water jet of Tu = 30 approximately 40%, and a water-air bubbling jet of Tu = 40 approximately 50%. Agreement betwe en the results obtained by the present velocimeter and those obtained by existing velocimeters, for example, Laser Doppler Velocimeter, hot wire anemometer and pitot tube was quite reasonable. Velocity measurem ent in a mercury-air bubbling jet also revealed the possibility of the usage of the present velocimeter for high temperature and high turbul ence molten metal flow in metallurgical reactors.