Pressure oscillation and steam cavity during the condensation of a submerged steam jet

Abstract

a b s t r a c tSteam jet condensation is important in many industrial applications. In this work, the pressure oscillation and steam jet patterns during submerged jet condensation in quiescent water is investigated experimentally. Firstly, it is found that even at stable condensation region, the steam cavity length varies all the time and steam bubbles separate from the steam cavity periodically. With the variation of steam cavity length and separated bubble oscillation, condensation also undergoes oscillation. Along the axial direction, the pressure oscillation intensity increases first and then decreases gradually. There is an distinct pressure oscillation peak, and the peak position varies over a length-to-diameter ratio range of X/D = 2 to X/D = 7. The axial position of pressure oscillation peak corresponds to the end of steam cavity. Moreover, oscillation energy analysis shows that the oscillation energy generated by separated steam bubble is much higher than that generated by the steam cavity length variation. Finally, based on the relationship between the axial distribution of pressure oscillation and the steam cavity, a method is proposed to determine the maximum steam cavity length by measuring the pressure oscillation distributions. The predicted deviation is only in range of ±16% for the test conditions.

Effect of non-condensation gas on pressure oscillation of submerged steam jet condensation

“…The oscillation power comparisons of the first and the second frequency bands revealed that, under the test condition, when air mass fraction increases from A=0% to A=5%, the maximum oscillation power of the second frequency band is always higher than that of the first frequency band, as shown in figure 17. This finding is similar to the results reported by Zhao et al(2015). However, after A>1%, the oscillation power gap between the two frequency bands decreases with the rise of air mass fraction.…”

“…The axial position of the oscillation peak also moves downstream gradually with rise of air mass fraction. As reported by Zhao et al (2015), the oscillation intensity peak is located at the end of the steam cavity. When air mass fraction increases, heat transfer coefficient of the steam-water interface decreases considerably (Choi et al, 2002;Liang and Griffith, 1994).…”

“…When water temperature is about 40-45 °C, it decreases suddenly. When water temperature is above 45 °C, oscillation intensity increases again (Zhao et al, 2015). In addition, the effect of air mass fraction on pressure oscillation intensity is investigated.…”

“…Chong et al (2015) proved that the second dominant frequency has always existed in the SC region, and the oscillation power of the second dominant frequency band was larger than that of the first dominant frequency band. Zhao et al (2015) investigated the distribution characteristic of condensation oscillation intensity at sonic jet condensation. They found that along jet direction, an oscillation intensity peak exists.…”

Characteristic of pressure oscillation caused by turbulent vortexes and affected region of pressure oscillation

“…Besides the first domain frequency, the second dominant frequency was found under certain test conditions [19]. Zhao et al [20] investigated the distribution of pressure oscillation intensity and found that its peak at the steam plume tail. Chong et al [21] released that the second dominant frequency was caused by separated steam bubbles.…”