Heat Transfer in Pipes to a Sodium-Potassium Alloy and to Mercury

Experimental data on heat transfer to liquid metals are often conflicting and do not accord with theoretical results. The reasons for these discrepancies have not been clear. The present work shows that the main reason for the disagreement is the thermal resistance between the heated surface and the liquid metal. This conclusion is reached from calculations of the heat transfer coefficient by two methods: from measurements of the temperature distribution in the moving liquid and from measurements of the wall temperature. The former agrees with the distribution calculated from Lyon's equation. It has been found that the presence of oxygen in a sodium-potassium alloy reduces the heat transfer coefficient. The results of experiments with no contact thermal resistance agree with those of Isakoff and Drew and of Brownet al.

A description is also given of the experimental apparatus, the test section, and a thermocouple whereby the temperature distribution in a stream of liquid metal can be measured.