In a pool boiling from an electrically-heated wire, there are three modes of boiling: nucleate, film, and coexisting nucleate and film boiling. These are shown in Figure 1. The latter has been studied by Semeria and Martinet (1 9 6 9 , Kovalev (1 966), Van Ouwerkerk (1972), and Madsen (1973,1979). Zhukov and Barelko (1983) found different states of mixed boiling.
In this work, the effects of the physical properties of heating wires on steady-state pool boiling were investigated analytically. The cases of constant voltage heating and constant current heating were solved.
Analysis
Consider the boiling of a liquid from an electrically heated wire suspended horizontally in a pool of a liquid. For a heating wire of diameter D and length L, the heat balance equation is
The initial condition is T ( x , 0) = f ( x ) . It is assumed that wire diameter is small compared to those of copper electrodes and that temperature of the electrodes is at the saturation temperature of the liquid. Thus, the boundary conditions are T ( 0 , t ) = T( L, t ) = Tsat. In dimensionless and steady-state form, the problem becomes
(3)
Function Fcontains qbo and q b , where qbo is a reference heat flux and is set to be 7.81 x lo5 W/m2 and qb is boiling heat flux that Correspondent concerning this paper should be addressed to S. M. Lu