STUDY OF AIR FLOW IN A ROOM WITH AND WITHOUT WALL TEMPERATURE DIFFERENTIALS

Abstract

Accurate prediction of velocity and temperature distributions in a room is indispensable for designing high quality air conditioning systems. This dissertation work is concerned with the feasibility and validity of numerical simulation of room air flow. Turbulent recirculating flows in many types of ventilated rooms were numerically simulated in three-dimensions using the k- e two equation turbulence model. Since 3-D simulation requires a large amount of computer storage and computational time it was impossible in the past to conduct such types of simulations wit sufficient accuracy due to limitations of computer resources. How ever, recent advances in computer technology and in numerical methods for fluid dynamics now make it possible to conduct such large scale simulations. In this study the air flow in a small scale room is simulated numerically using two different turbulent models those are k- e two equation model and Large Eddy Simulation. The air flow patterns are very complicated since heat and momentum sources are distributed. The supply air devices can not be described in detail without the computational grid becoming impractically large. Therefore, an integral part of a CFD simulation is to simplify the actual flow situation with out losing essential features of the flow. In this study two different room models are considered. Room is cubical in shape and has one inlet and two outlets In one model wall temperature differentials is considered whereas in the other one wall temperatures are constant. For both cases the vector plots of velocity and contour plots of air velocity are studied. For the wall temperature differential model the temperature profiles are studied.