Cooling air temperature reduction and local heat transfer in a pre-swirl shrouded rotor-stator system

摘要

Pre-swirl nozzles arc often used to deliver the cooling air to the rotating turbine blades in the cooling systems of gas turbine engines. In this paper, a new method which using guide vane to deliver the cooling air was proposed. An experimental study has been undertaken to investigate the influence of gap ratio, mass flow rate, swirl ratio, and rotational Reynolds number on the total temperature reduction and the local heat transfer in a shrouded rotor-stator system with pre-swirled air which is produced by the nozzle and by the guide vane, respectively. In additional, this paper describes how a thermochromic liquid crystal (TLC) in conjunction with a digital camera is used in a steady experiment to obtain temperature field on the rotating disk. The results of experiment reveal that the total temperature reduction decreases and the local heat transfer deteriorates with the increase of the rotational speeds, or with the decrease of mass flow rate and swirl ratio, whatever the cooling air is swirled by the pre-swirl nozzle or by the guide vane. The total temperature reduction is decreases for the pre-swirl nozzle and increases for the guide vane with the increasing gap under the conditions of experiment. The contours of temperature on the rotating disk take on the shape of concentric circle where have a distance from the receiver holes from the images of TLC, the heat transfer is best where opposite to the pre-swirl nozzles or guide vanes on the rotating disk. The effect of heat transfer received by guide vane is no better than that of pre-swirl nozzle in most conditions as a whole.