CFD DEVELOPMENT AND SIMULATION OF FLOW FIELDS IN VENTILATED SPACES WITH MULTIPLE OCCUPANTS

摘要

Simulation of flow fields in ventilated spaces with multiple occupants (cows) was conducted using a computational fluid dynamics (CFD) technique. Airflow in a ventilated space is affected by the locations of the inlet and outlet, inlet or room shape, and positions of the occupants. Three simulation test cases considered are: (1) four cows standing in a row with one end wall simulating as an inlet, and the opposite end wall simulating as an outlet; (2) four cows standing in a row with the two end walls simulating as inlets, and an outlet located at the center of the ceiling; and (3) ten cows placed at random with inlet and outlet arrangements the same as in Case (2). The body-fitted coordinate (BFC) system is adopted to characterize the shape of a cow, and the governing equations in the Cartesian coordinate system are transformed into the BFC system. To generate the grid under the BFC system, partial differential equations and algebraic interpolation methods were used. The finite volume method is applied to transform the partial differential equations into algebraic ones, and the SIMPLE (Semi-Implicit Method for Pressure-Linked Equation) algorithm is extended to the BFC system to solve the flow field. The effects of obstructions (cows), and the positions of cows, inlets, and outlet on flow distribution were clearly demonstrated by velocity vectors, velocity profiles, and streamline plots generated. The flow field was more evenly distributed when cows were positioned at random than when in a row