Experimental investigation of unsteady convective heat transfer under airflow velocity and temperature variations

An experimental approach to study unsteady local heat transfer characteristics due to airflow velocity and/or airflow temperature variations is presented. It uses controlled electrical heaters and rotating vanes to independently vary the flow and thermal boundary conditions. Time-resolved surface temperatures are measured using an in situ calibrated infrared thermography camera. Those surface temperatures are analyzed by modeling the transient conjugate heat transfer process in the wall to obtain locally resolved surface heat flux distributions. The applicability is illustrated for a flow and heat transfer behind a tetrahedral vortex generator on a flat plate.