Numerical Investigation of Velocity and Temperature Effects on Flow Patterns in Displacement Ventilation

Indoor environmental conditions and air distribution are critical factors affecting the performance of ventilation systems in residential buildings. This study investigates the effects of inlet air velocity and temperature on airflow patterns and thermal stratification in a space equipped with a displacement ventilation system. The space was modeled based on ASHRAE Standard Case ۶۰۰, with dimensions ۸ × ۶ × ۲.۷ m, two wall-mounted supply vents, and two ceiling exhaust vents. Inlet air temperatures of ۳۵, ۴۰, and ۴۵ °C and velocities of ۱ and ۲ m/s were considered. The numerical simulations were performed using ANSYS Airpak with a structured mesh and the RNG k-ε turbulence model. Boundary conditions included insulated walls and windows with specified heat transfer coefficients. The results show that increasing the inlet air velocity significantly enhances air mixing and raises the average room temperature, while variations in inlet air temperature within the studied range have negligible effects on the velocity distribution. Flow patterns indicate that at low velocities, buoyancy effects dominate, leading to upward movement of air from the supply vents, whereas at higher velocities, the airflow penetrates longer distances along the room before rising. These findings emphasize the significant impact of inlet air velocity and temperature on flow patterns and temperature distribution in displacement ventilation systems. The study provides useful data for designers to optimize system performance and ensure more uniform air distribution within spaces.

کلیدواژه ها:

Displacement ventilation ، CFD ، Case ۶۰۰ ، Temperature distribution