Experimental study on jet boundary characteristics of square ceiling diffusers

Through the multi-case isothermal experiments of four different sizes of square ceiling diffusers at the throat wind speed of 2 to 5 m/s, studies the jet flow characteristic parameters such as jet diffusion width, descent distance and throw of the square diffuser. Analyses the variation characteristics of jet boundary by drawing the envelope of the jet. The results show that the air supply jet of the four sides of the square ceiling diffuser has the three-stage characteristics. The whole air supply range is 3 to 12 m, which can form a good flat jet in the ceiling, the maximum drop distance of the attached jet is 0.87 m. The return flow of jet has a certain effect on the uniform distribution of indoor temperature and the good indoor thermal comfort environment. Based on the experimental data, obtains the multiple regression formula of the diffusion width and range of a single jet.