Heat Transfer Performance of Sodium Encapsulating Engine Valves

抄録

The performance of a hollow engine valve encapsulating sodium in the cavity was investigated experimentally and theoretically. This type of valve has been practically applied to improve heat transfer. In this study, 3D finite element heat transfer analysis and experimentation were conducted at a maximum temperature of 343 K to eliminate the effects of phase transformation; sodium is solid and does not vaporize in this temperature range. These results were then compared with previously reported results at a maximum temperature of 1073 K. The empirical temperature distribution of the sodium encapsulated valve was consistent with the calculated temperature distribution at a maximum temperature of 343 K. However, the empirical temperature distribution at 1073 K did not agree with calculated results. Instead of collecting in the bottom (head side) of the valve, apparently, sodium collects on the inner surface of the cavity at higher temperatures likely due to sodium vapor deposition.