Additives which can significantly enhance the nucleate pool boiling of acetone and Freons have beenfound in experiments.The boiling heat transfer coefficients of the working fluids can increase by 3 to 5 timeswith trace amount additives.The mechanism of enhancing the boiling of the organic fluids with additives hasbeen investigated.

The hard-sphere three-parameter equation of state(CSPT)proposed in the previous paper(Li et al.1991)was modified by a new temperature relation for the pseudo-critical compressibility ξand the temperaturecorrection factor α(T_r)of the attractive parameter.Vapor pressures and Saturated liquid densities of 105 purecompounds were calculated by the modified version.Results show that correlations of saturated properties at lowreduced temperatures and thermodynamic properties in the vicinity of critical region were significantly improved.Furthermore,characteristic parameters of this modified version were generalized by acentric factor ωand criticalcompressibility Z_c to predict saturated liquid densities of 72 polar substances and the latent heat of vaporizationfor 151 substances including strongly polar compounds with satisfactory results.

A new non-cubic equation of state is proposed for calculation of the thermodynamic properties ofnonpolar and polar fluids and their mixtures,including,saturated vapor pressure,saturated liquid volume,saturated vapor volume,heats of vaporization and vapor-liquid equilibria.The new equation is derived from thegeneralized van der Waals partition function in which the repulsive terms are expressed with the Carnahan andStarling equation for hard spheres,and the attractive terms are made up of the dispersive energy and theChemical association energy. The rules of dependence of parameters αand σand on temperature are considered broadly so that the newequation yields good agreement with experimental saturated properties of 20 nonpolar and 27 polar fluids in therange of reduced temperatures of 0.5 to 1.0 The new equation with parameters group-contributed generally givessatisfactory predictions on saturated properties. Correlations of vapor-liquid equilibrium data for alcohol-containing systems by using van der Waalsone-fluid mixing rules prove that the new equation is superior to the M-PR equation of state.

In this paper,the mechanism of operation of an inverse circulating thermosyphon evaporator isproposed.The performance characteristics of this novel evaporator have been studied experimentally andtheoretically,The inverse circulating thermosyphon evaporators have higher heat transfer coefficient and longeroperation period in comparison with ordinary circulating ordinary circulating evaporators.