Numerizing of Heat Transfer Coefficient between Water Spray and Heated Metal Specimens
Masashi MITSUTSUKA
pp. 685-693
Abstract
The author made four kinds of water spray cooling experiments to numerize heat transfer coefficient h between water spray and a heated specimen as a function of water flux W, water pressure P and specimen surface temperature θs. In this report, the author described numerizing of the equation: h=f (W, P, θs). The specially fixed water flux Wd (W1 to W4), water pressure Pd (P1 to P4), specimen surface temperature θsd (50, 75, to 900°C), and the most probable values of heat transfer coefficient hsa obtained from these experiments were introduced for numerizing of the above-mentioned equation.
The principal contents are as follows: (1) In each θsd, the exponents n1 to n4 of the equation: hsa=AWnd corresponding to Pd: P1 to P4 respectively were obtained (A is constant). The mean exponent n is (n1+…+n4)/4. (2)In each θsd, the exponents m1 to m4 of the equation: hsa=BPmd corresponding to Wd: W1 to W4 respectively were obtained (B is constant). The mean exponent m is (m1+…+m4)/4. (3) By using n and m, the equation: h=C(WnPm) among arbitrary W, arbitrary P and h was numerized in every θsd (C is constant). (4) hi and hi+1 corresponding to θsd: θsdi and θsdi+1 respectively were calculated by using the equation: h=C(WnPm). Next, by using the relations: [hi vs. θsdi] and [hi+1 vs. θsdi+1], the equation: hx=f(θsx) to obtain hx corresponding to an arbitrary θsx between θsdi and θsdi+1, was numerized.
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