Temperature and pressure oscillations induced by steam direct contact condensation in a T-junction with porous inner-structures

Abstract

Steam direct contact condensation (SDCC) has been investigated experimentally with the steam mass flow rate in the range of 2 ~ 60 kg/h, the subcooled water flow rate in the field of 0.5 ~ 2 m3/h and the subcooled water temperature at 30 °C.in an empty T-junction and the T-junction with two porous inner-structures (made up by stainless steel ball with two different diameters). The effects of different porous inner-structures on temperature and pressure oscillations were investigated with different saturated steam mass flow rate and subcooled water flow rate. The results show that the porous inner-structures significantly reduces the temperature fluctuation near the branch pipe. Then, the positive peak value of pressure oscillation increases firstly and then decreases with the increase of porous inner-structures porosity. the intensity (RMS) of pressure oscillations were suppressed by filling the porous inner-structures. Besides, filling the porous inner-structures increases the viscous resistance and inertia resistance of the flow and enhances the intensity of turbulence. So the first dominant frequency increased significantly as the porosity of porous inner-structures decreased. Especially when the porosity ε = 0.318, the increase of the first dominant frequency is particularly evident and the maximum even reached 463 Hz.