Measurement of temperature and local vapor content profiles near the heat transfer surface with water pool boiling

Presented are the experimental results of simultaneous measurement of temperature and local vapor content profiles near the horisontal heating surface during the process of saturated boiling of distilled water at atmospheric pressure in the heat flux range of g=(490-1440)x103W/m2. The measurements of temperature profile in the superheated layer were carried out by means of nichrom-constantan microthermocouple, and for the measurement of local vapor content electric resistance probes were used. The microthermocouple and probes were integrated into a detector assembly. It has been established that the values of the superheated layer extrapolated thickness and height of maximum vapor content are interconnected by exponential dependence, and the values of heat transfer coefficients are proportional to the value of the maximum vapor content in the near-to-wall layer. The results of measurement of the superheated layer extrapolated thickness and the local vapor content profiles are in good agreement with the data obtained by other authors. It has been found using the vapor content measurement that it is possible to obtain relations between surface parts occupied by vapor and liquid during the nucleate boiling