Study on Influence of Branch Blind Pipe on Hydraulic Transients in Loading System of Launch Site

Abstract

Influence of branch blind pipe in propellant loading system of rocket launch site on hydraulic transient in pipes is studied using computational fluid dynamics (CFD), and effects of branch blind pipe's existence, geometrical size as well as its location on hydraulic transient is analyzed, results reveal that (1) the influence of branch blind pipe on hydraulic transient is significant, and (2) relatively short branch blind pipe would increase the transient pressure peak, but longer the branch blind pipe is, less the increasing magnitude is, and slower the pressure fluctuation damping is, (3) meanwhile smaller diameter of blind pipe would also lead to higher transient pressure peak, but faster pressure fluctuation damping, (4) additionally, the branch blind pipe's location on the main pipe has limited effect on hydraulic transient. This study is meaningful for optimizing the configuration and pipe distribution of loading system, and controlling pressure fluctuation in pipes as well as ensuring the security of loading process. The significant traits of loading system, comparing with other pipe networks, are its substantial pipes and the complicated way they link to each other. When propellant loading, a pipe may be cut off by a closed valve on it, but part of the cutoff pipe (PCP) may still link to circulating pipes (CP). When flow fluctuation in CP occurs due to hydraulic transient, propellant in PCP would be affected and further influence fluctuation in CP. Studies on influence factors of hydraulic transient in pipes in the past usually concentrated on actions of components which would trigger the flow fluctuation such as valves (6) and pumps, and dampening effect of equipment such as surge tower and check valve installed intentionally to weaken the transient pressure, little attention was paid on influence of PCP on hydraulic transient. Therefore, this paper will explore the relationship between PCP and hydraulic transient using CFD, 3-D model will be used during computing for influence details research. Fundamental Physical Model