Boiling on the surface of a rotating disc

Δημοσίευση σε επιστημονικό περιοδικόSummarization: An experimental unit to study heat-transfer characteristics while boiling at subatmospheric pressure of a horizontal smooth spinning disc was designed and built. Evaporation experiments were carried out with the speed of rotation varying from 0 to 1000 rpm and the feed flow rate from 1 to 5 litre/min. The boiling temperature varied between 40 and 50 °C. Water and corn syrup were used as test liquids. Results are presented from the experimental measurement of the heat flux on the disc as a function of the wall superheat. The heat-transfer coefficient for water, in the low range of heat flux (10–30 kW/m2), increased from about 2 to 9 kW/m2K when the speed of rotation increased from 0 rpm to 1000 rpm. In the upper range of heat flux (60–100 kW/m2), it increased from about 5 to 16 kW/m2K for the same increase in the speed of rotation. The feed flow rate between 1 and 5 litre/min had no significant influence on the heat-transfer coefficient in the range of 200–600 rpm. With the 60 °Brix corn syrup, the heat-transfer coefficient at 10 °C temperature difference increased from about 0.8 to about 2.3 kW/m2K when the speed of rotation increased from 0 to 1000 rpm. A simple theoretical relation was derived which predicts the heat-transfer coefficient for water at inlet Reynolds numbers 500–1000 relatively well, but underpredicts the results for corn syrup at inlet Reynolds numbers 10–100.Παρουσιάστηκε στο: Journal of Food Engineerin