关键词: 两相流, 流体力学, 电子压力扫描阀, 功率谱密度, 换热管

Abstract:

Heat exchangers, as vital energy conversion devices in chemical engineering, face significant challenges due to flow-induced vibrations (FIV) of tube bundles, which are a crucial factor in inducing vibration fractures. The safety and reliability of these systems become particularly critical. In engineering calculations of the vibrational response caused by FIV, it is necessary first to determine the power spectral density (PSD) of the fluid excitation forces, which requires extensive testing data of the fluid excitation forces. This paper designed a special structure heat exchanger tube and conducted experiments in a two-phase flow water tunnel using an electronic pressure scanning valve, validated by reliable accelerometer testing methods. The results demonstrated that the testing method proposed in this paper could accurately measure the fluid pressure exerted on the tube bundles under two-phase flow conditions without affecting the surrounding flow field. At lower gas content, vortex shedding occurred, and both lift and drag increased with rising gas content. An increase in gas content disrupted vortex formation, exacerbating vibration damage during turbulent flutter of the tube bundles. The dimensionless reference equivalent power spectral densities obtained using two conversion methods were highly consistent. The experimentally obtained PSDs were compared with the dimensionless reference equivalent PSDs determined by other researchers, showing overlapping data sets and similar overall trends, thus validating the rationality of the testing method described in this paper. This testing method could provide foundational data support for the design, operation, maintenance, structural improvement, and safety assessment of steam generators.

Key words: two-phase flow, fluid mechanics, electronic pressure scanning valve, power spectral density, heat exchange tube