A heat conduction simulation of a spark plug weakly coupled with combustion was developed. As one of the dominant parameters of the spark plug, the heat flux between combustion gas and a spark plug was then evaluated. Computational cost was drastically reduced through modeling turbulent heat transfer rate and gas temperature in the vicinity of a spark plug as functions of surface temperature of a spark plug and crank angle. The simulation was validated with experimental data. Parameters tuning in turbulent heat flux model is requisite, and then it minimizes the discrepancy in the spark plug temperature between the simulation and the experiment within ±10%.

抄録全体を表示

In our present civilization, forced convection cooling is used in wide-ranging situations from cooling of microprocessors to that of heat engines. Active cooling is essential in such situations to avoid thermal failure (for microprocessors) and maximize fuel-to-work conversion efficiencies (heat engines). However, such active cooling causes rapid destruction of the exergy of thermal energy transferred from the heat source. This issue has remained unaddressed despite the widespread use of forced convection cooling. In this study, to partially recover presently lost exergy in such situations in the form of electricity, we integrate thermo-electrochemical conversion, which has mostly been studied for statoinary conditions using a liquid electrolyte encased in a closed vessel, into forced convection cooling. We design a test cell in which an electrolyte liquid is forced through a channel formed between two parallel electrodes and the hot-side electrode simulates an object that needs to be cooled. Through experimental and numerical investigations of the test cell, cooling and power generation properties of such a forced-flow cell are elucidated. It is demonstrated that such a forced-flow thermo-electrochemical cell can generate more electric power than the hydrodynamic pump work required to drive the liquid through the cell.

抄録全体を表示