Estimation of local nucleate boiling heat flux using a three-dimensional transient heat conduction model

Boiling heat transfer is still hard to model and to predict. Among all kinds of studies on boiling processes, the estimation of the local heat fluxes at the boiling surface is fundamental. In this article, we solve a three-dimensional transient inverse heat conduction problem (IHCP) arising from a single-bubble nucleate boiling experiment to reconstruct the local boiling heat flux from a high-resolution temperature field measured at the back side of a thin heating foil. From the mathematical point of view, this problem belongs to the class of ill-posed inverse problems and cannot be solved straightforwardly by classical numerical methods. Thus, an iterative regularization strategy based on the conjugate gradient method is applied to the solution of the considered IHCP. Ring-shaped local boiling heat fluxes which undergo a significant change during a single-bubble cycle are observed.