Identification of heat flux and heat transfer coefficient during water spray cooling of horizontal copper plate

摘要

Heat transfer coefficient (HTC) and heat flux (HF) at the copper plate during water-air assisted spray cooling from 700 degrees C to the ambient temperature was evaluated. For the HTC and HF identification the inverse method has been implemented. A self-developed computer code based on finite element method (FEM) has been used to solve the heat conduction problem. The FEM solver utilizing linear and nonlinear shape functions has been first compared with the analytical solution to the plate cooling. Further, the reduced finite element model employed in the inverse solution has been compared with the reference model for plate cooling under variable in time and space HTC. The boundary condition at the water spray cooled surface obtained from earlier researches has been employed in the uncertainty tests. The conducted tests have allowed determining the uncertainty of the inverse solution to HTC. A part of research includes the experimental study, which consist of the temperature measurements inside the copper plate during water spray cooling. The measured temperatures have been used as an input data for the local HTC and HF identification and development of a local HTC and HF models. The models have allowed retrieving the water flux rate, fluid pressure and the nozzle to plate distance influence on the boiling curve parameters. The boundary condition models define HF and HTC as functions of a local plate surface temperature.