Optimizing Research On Ductless Inductive Ventilation System For Underground Car Parks

Compared with traditional duct ventilation system, ductless inductive ventilation system is more and more popular for its space-saving, high ventilation efficiency and easy to maintenance and regulation. But, its design method is lack of mature theoretic sustainment. So after obtaining the correct mathematical model and boundary conditions, there are numerical simulations by using the special CFD software. The simulations on basis of the two-equation turbulent model were made by the method of control cubage .Discrete equations were solved with the SIMPLE algorithm, and the velocity and concentration distributions were drew in the underground car park.In order to obtain the correct mathematical model and boundary conditions, this paper measured the velocity of a single inducement fan. Based on this, the physical model was built in accordance with the real situation, and the numerical simulations were performed. After repeating simulations, comparing the test results and simulation results and modifying the mathematical model and boundary conditions, the correct mathematical model and boundary conditions were obtained, which were the foundation for latter simulations.Because there are so many factors affecting the ventilation efficiency of ductless inductive ventilation system, only several important factors were researched in this paper, such as the distance from inducement fan to front or back barrier, horizontal spacing between inducement fans and arrangement of the main trunk line. According to the comparison and analysis of velocity or concentration distributions, the preferable values for the factors were confirmed and they will be the basic data for the design of ductless inductive ventilation system. In this paper, the data were used in the design of ductless inductive ventilation system for an underground car park in the city of Tianjin and the ductless inductive ventilation system was simulated. The results of simulation indicate that the concentration of CO can satisfy the requirement of criterion.Furthermore, this paper compared the ventilation efficiency in the situations of on and off for inducement fans. The results show that the concentration distribution of CO is more uniform and the ventilation efficiency is higher for turning on inducement fans, and the ductless inductive ventilation system plays a good role of dilution.