Study of the leakage tracer gas transport property in condenser: Hellium and Sulfur-Hexafluoride

Abstract

Helium (He) tracer method is one of the common methods used to detect tube bundle leakage in the condenser. To improve the detection accuracy, sulfur hexafluoride (SF6) is considered a tracer gas instead of He. This paper combines the N-S equation, porous medium model, flow diffusion model and steam heat transfer model to develop the numerical model of tube bundle leakage in the condenser. The simulation results show that the transport of leaked gases (He and SF6) consists of flow and diffusion patterns. The existence of the diffusion process is confirmed further through theoretical analysis. The two gases have the same transport behavior in the pure flow process. When it involves the diffusion process, the flow rate of He is 6.67 times that of SF6. In other words, the time required for He to reach the same concentration difference is 1/6.67 times that of SF6. In addition, the influence of leakage intensity and gas species on the transport is analyzed. The study results provide a theoretical basis for SF6 to replace He as a tracer gas to detect tube bundle leakage.