Masaharu Watabe

Multi-Stage Solid Oxide Fuel Cell: Gas Turbine Combined Cycle Hybrid Power Plant System

Today, the need to develop more efficient thermal power systems that emit less greenhouse effect gas has become a paramount importance. In line with this awareness, our research has leapt into such development that the combination of SOFC and Gas Turbine could generate power at extremely high efficiency. In this paper, we would like to present our concept of Inter Cooled Multistage SOFC-GT Hybrid Power System, developed to maximize fuel heat input to the system. We propose the combination of F-class GT (TIT 1350°C class) and 5 stage SOFC as the best for the hybrid power plant system and 77% (LHV base) is achieved at high pressure ratio.Copyright

Laminar forced convection condensation of binary mixtures on a flat plate.

This paper deals with the theoretical analysis of laminar forced convection condensation of binary mixtures on a flat plate. Similarity solutions for seven kinds of binary mixtures of ethanol-water, R 22-R 114, R 114-R 11, air-water, air-ethanol, air-R 22, air-114 along with several pseudo-mixtures of low Shmidt number and low ρ-μ ratio are numerically obtained. Two expressions among the boundary values at the vapour-liquid interface concerning heat and mass flaxes through the vapour boundary layer are newly proposed, which contain the characteristics of condensation of superheated and saturated pure vapours and those of single phase forced convection. The heat and mass fluxes calculated from the simultaneous algebraic equations which are composed of the present new expressions, previous expression for liquid film heat transfer, phase equilibrium conditions and miscible condition, agree with those from the similarity solutions within 1-3% error.

二成分混合蒸気の凝縮における気相境界層の代表物性値 : II 層流自由対流凝縮の場合

The numerical analysis is made for free-convection condensation of binary vapor mixtures quite similarly as the case of forced-convection condensation. The physical properties which are evaluated at the arithmetic mean of the mass concentrations at the vapor-liquid interface and the bulk and the corresponding saturation temperature are recommended as the representative ones in the case of the algebraic solution.

Laminar Forced-Convection Condensation of Saturated Vapors in the Subcritical Region.

A numerical analysis is presented for laminar forced-convection condensation of saturated vapors of water and carbon dioxide on a flat surface in the reduced temperature range TS/TC=0.990∼0.999. The heat transfer coefficient in the region TS/TC<0.998 can be correlated by using Fujii and Ueharas equation for constant physical properties when the representative physical properties are evaluated at the film temperature. The reduction of condensation mass flux or the heat flux at the vapor-liquid interface due to the convection term in the film is expressed as a function of the phase change number with the average isobaric specific heat.