Characteristics of instantaneous heat transfer rates in three heat-transfer-coefficient regimes

摘要: Abstract Instantaneous heat transfer coefficients (h) for flows of various fluids (mercury, air, water, and motor oil) over plates inclined at angles have been fundamentally examined. We discovered three distinctive regimes, in which behave interestingly. In regime I, as h increases, instantaneous rates (q) decrease, defying our physical intuition. Regime II exhibits maxima q-versus-h curves. III, becomes a strong function time especially t ∈ [ 0 , 1 s ] revealing the possible deficiency traditional lumped-capacitance models. Results computational simulations are obtained using COMSOL commercial package whose algorithm is based on Galerkin finite element method, exhibit qualitatively-correct trends when compared with classical solutions steady-state cases.