Minimum film boiling temperature and minimum heat flux in pool boiling of high-temperature cylinder quenched by aqueous surfactant solution

Abstract

The use of surfactant has been known as one of effective ways to improve the boiling heat transfer. However, the most of boiling research using the surfactant has focused on the nucleate boiling regime, and the surfactant effect on the MFB (minimum film boiling) point, identified with MFBT (minimum film boiling temperature) and MHF (minimum heat flux) has rarely been studied. In the present study, the effects of surfactant and liquid subcooling on MFB point of vertical stainless steel cylinder were investigated experimentally using the quenching method. As the test fluids, the aqueous SDS (sodium dodecyl sulfate) solutions (1000 wppm and 2000 wppm), known to enhance the nucleate boiling heat transfer, were tested with pure water, where their liquid subcoolings covered from 0 °C to 39 °C. Based on the present experimental data, it was revealed that the SDS surfactant can impede the MFB point, while the increase of liquid subcooling leads to accelerating the MFB point. In addition, the influence of contact angle on MFB point was examined and discussed in detail. It was found that it could be insufficient and limited to explain the general trends of MFB point using contact angle alone and the fundamental factors responsible for changing the contact angle and thermal-hydraulic conditions should be considered.