Assessment of spallart almaras turbulence model for numerical evaluation of ceiling fan performance

Abstract

Ceiling fans are a popular means of providing thermal comfort to occupants in an indoor environment, mainly in tropical countries and it contributes to a significant portion of annual energy consumption throughout the world. It is proven that using ceiling fans in conjunction with air conditioners in an air-conditioned environment can lead to higher thermal comfort at a lower cost of energy which will in turn increase the popularity of the ceiling fans in near future. Understanding the proper flow field around a rotating ceiling fan can lead to design more efficient fan blades, which can lead to significant energy savings. Analyzing these using experimental methods is both a tedious and a costly task. By using numerical methods, this can be achieved at a significant lower cost and effort. For such analyses, CFD methods using RANS equations are widely used for both indoor and outdoor conditions. For this purpose, numerous turbulence models are available, each of which would more accurately predict some cases than others. Therefore, Standard KE, Standard KW, RNG KE and Spalart Allmaras model is evaluated for a case of efficiency assessment of ceiling fans and SA model was found as the most accurate model with just 1.9% NRMSD with experimentally calculated values.