Effect of the air supply angle of swirling diffusers on the air diffusion performance index in a vehicle assembly workshop

Abstract

Airflow improvement in a large industrial building is one of the most effective ways to improve the thermal comfort of workers. Air Diffusion Performance Indices (ADPI) of an industrial workshop area under different air supply angles (15°, 30°, 45°, 60°, 75° and 90° in summer and 90° in winter) of the ceiling-mounted swirling diffusers were evaluated by on-site measurements and computational fluid dynamics (CFD) modelling. The measurement data was used to verify the CFD numerical model. The temperature and velocity field of the working area were simulated and analysed under seven operating conditions of swirling diffusers. The findings showed that in summer, the increase of the swirling air supply angle would increase the air velocity. When the air supply angle was larger than 75°, a draughty wind speed (>0.3 m/s) in the local working area, was produced. When the air supply angle was 30°–75°, the indoor design comfortable temperature range (26°C–28°C) was produced. The ADPIs of the workshop were 100% with the air supply angles of 45° and 60° in summer and 90° in winter, respectively. The research findings should provide a reference for improving the airflow organization in the working area of a tall factory building.

Indoor non-uniform environmental characteristics of local convection heating and its background radiation field correction

“…Introduction of P-ADPI. The air distribution characteristic index ADPI 27 is the percentage of people who feel comfortable indoors; it is used to measure the thermal comfort of people in a uniform local heating environment. It is the ratio of the number of measuring points with temperature and wind speed meeting the effective temperature difference (4ET) between À1.7 ∼ + 1.1°C and the total number of measuring points, which can be calculated using equation ( 3) Equation ( 4) determines the effective temperature difference (4ET) with indoor temperature and velocity…”

Ventilation Efficiency According to Tilt Angle to Reduce the Transmission of Infectious Disease in Classroom

“…The operating conditions of HVAC systems affect not only droplet transmission, but also many factors, including operating costs, ventilation effects and thermal comfort conditions. [15][16][17] Since the tilt angle of the HVAC system, one of the various operating conditions, was an important factor in determining the indoor flow pattern, various studies have been conducted. 18,19 Xin et al 20 studied the operation performance and energy consumption of the standing type of air conditioners according to different installation positions, and they showed that the optimum cooling performance and removal of volatile organic compounds (VOC) occurred when the standing type of the air conditioner was installed diagonally opposite the door.…”