SIMULTANEOUS MEASUREMENT OF VELOCITY AND TEMPERATURE FIELD IN THE DOWNSTREAM REGION OF A HEATED CYLINDER

摘要

Simultaneous measurements of the flow velocity and temperature field for a heated bluff body present a typical problem. We attempted to cany out simultaneous measurements using two different methods, Particle Image. Velocimetry (PIV) and Schlieren. In this experiment, an electrically heated circular cylinder is placed in a parallel flow, in a wind tunnel The experimental tests were carried out at low Reynolds numbers (Re<200), therefore, the flow field was approximately two dimensional (the same flow in every normal plane of the heated circular cylinder). Two-dimensional flow and the principle of the Schlieren measurement technique were used to visualize the temperature field. The Z-type Schlieren technique was applied to measure the temperature distribution. Experiments were carried out for forced convection in a 500x500 mm cross-section wind tunnel. The measurement technique and results were shown at different cylinder surface temperatures. The relationship between the vortices shed from the heated cylinder and the heat transfer was determined by relevant numerical simulations. The main objective of the present experimental investigation is to find out whether both velocity and temperature can be measured at the same time. Results are promising and indicate that this aim can probably be met with further refinements of the technique.______________