Pool boiling heat transfer and quench front velocity during quenching of a rodlet in subcooled water: Effects of the degree of subcooling

ABSTRACT

Pool boiling heat transfer and quench front propagation were investigated during quenching of cylindrical stainless steel rodlets in subcooled water. The degree of subcooling was varied from 0°C (saturated) to 40°C at an increment of 10°C at atmospheric pressure. The results showed that the increase of degree of subcooling accelerates quenching, with the total quenching time being shortened from 90 second (saturated) to 12 second (subcooled by 40°C). As revealed by the boiling curves that were obtained via solving an inverse heat conduction problem in cylindrical coordinates, boiling heat transfer is enhanced significantly for all boiling modes with raising the degree of subcooling. At the highest degree of subcooling of 40°C, the critical heat flux is improved by nearly 300% as compared to that in saturated water. In addition, the rewetting temperature (i.e., Leidenfrost point) was found to increase as a nearly linear function of the degree of subcooling. The quench front was observed to propagate upward from the bottom of the rodlet, which is accelerated noticeably with increasing the degree of subcooling. The average quench front velocity was shown to agree well with the predicted value of an existing theoretical model that was modified to take the influence of subcooling into consideration.

KEYWORDS:

• Critical heat flux
• quench front
• rewetting
• rodlet
• subcooling

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Funding

This work was supported by the China National Key R&D Program [2016YFB00005004]; National Natural Science Foundation of China (NSFC) [51206142]. A start-up fund granted to L.-W. Fan by the “100 Talents Program” of Zhejiang University is also gratefully acknowledged.

Additional information

Funding

This work was supported by the China National Key R&D Program [2016YFB00005004]; National Natural Science Foundation of China (NSFC) [51206142]. A start-up fund granted to L.-W. Fan by the “100 Talents Program” of Zhejiang University is also gratefully acknowledged.