This work is concerned with the thermal design of portable projection display equipment (i.e., a portable projector). The portable projector is being made smaller and lighter to better serve the carrier, while its luminance is enhanced to benefit the viewer. The confluence of these demands increases the thermal loading on the projector. The design of cooling airflow path is becoming evermore important; however, the complex internal organization of the projector hampers an attempt to conduct flow and heat transfer analysis. A particularly important issue for the projector designer is to predict the effect of shrinking box size of the next generation product on cooling airflow. This paper describes a way to foresee the effects of reducing the key geometric dimensions of the projector on the distribution of airflow. The analysis is conducted using a computational fluid dynamics (CFD) code. CFD results are obtained on sampled points in the parameter domain and used to find the effects of various geometric parameters on the airflow rates. The sampling and screening of CFD results follows the Taguchi method (or the method of experimental design). The most influential parameters for the total airflow rate and the airflow rate over the electronics board are identified. This conclusion, however, is only an illustration of how the CFD analysis can assist the equipment designer in planning the next generation product. The methodology reported here can be applied in the plan and design of other electronic equipment that have similarly complex internal organizations in shrinking system boxes.