Design and Simulation of Multi-gradient Negative Pressure Control System in Confined Space

Confined spaces with hazardous airborne effluent, such as nuclear facilities and medical facilities, often need to form multi-zone and multi-gradient negative pressure space through negative pressure control system. In such a negative pressure system, what often puzzles the designer is how to determine the key parameters of the ventilation system equipment under the condition of considering the leakage air volume. In this paper, theoretic calculation; MATLAB Simulink simulation and CFD simulation are used to determine and validate key values of a ventilation system consist of a fixed-flow centrifugal fan and two regulating dampers. In the CFD simulation, dynamic grid coupled with UDF is applied to predict the steady state distribution of flow field in the confined space. The operating range of fan flow-rate and damper position are calculated after estimation and validation.