It was the intent of this investigation to determine boiling film coefficients of SO₂ in a temperature range not previously investigated. Further, a practical method of circulating liquid SO₂ and reclaiming SO₂ vapor without a compressor or pump was attained.

For the range investigated the boiling film coefficients decreased with an increase in temperature difference between the boiIing SO₂ liquid and the surface of the heater. This occurred in the regime of partial nucleate boiling. Favorable comparisons were made with the limited information available for this bolling regime.

It was found that the controlling film coefficient was on the steam side of the test evaporator. This was due to the comparatively large values obtained for SO₂ bolling film coefficients. Within the limits of this investigation, the overall heat transfer coefficient may be taken as approximately equal to the steam film coefficient.

Much more work needs to be done in the regime of partial nucleate boiling as the available literature is far from complete.