Solar powered thermoacoustic engine is an attractive device for solar thermal utilization. Its performance is significantly affected by tilt angle when it rotates with the sun. In this study, the heat transfer and flow characteristics of thermoacoustic engine were investigated under five tilt angles including -45 degrees, -90 degrees, 0 degrees, 45 degrees and 90 degrees. The temperature and velocity fields of thermoacoustic core were measured respectively by Thermal Infrared Imager and Particle Image Velocimetry (PIV). Experimental results show that acoustic oscillation has significant influence on the flow and heat transfer in thermoacoustic engine. This kind of influence is different when thermoacoustic engine works under different tilt angles. Five tilt angles were classified into three situations according to the relative position of two heat exchangers. And the interaction of thermal convection and acoustic oscillation was discussed in each situation. (C) 2014 Elsevier Ltd. All rights reserved.