EXPERIMENTAL INVESTIGATION OF HEAT EMISSION FROM A BOILING SOLUTION OF CAUSTIC SODA IN A VERTICAL TUBE WITH NATURAL CIRCULATION
Results of investigations in the determination of heat emission with boiling solutions of caustic soda, NaOH, in a vertical tube with natural circulation are presented. The object of this research was to obtain data for reliable calculation of heatlng surfaces in equipment for the evaporation of NaOH solutions and to establish optimum operating conditions. A system of specially designod experimental equipment is described. The methods of measurement and of processing the experiments are described in detail. In particular, the specific heat flow q was determined by the quantity of condensate formed on the surface of the boiling tube at separate sections, the quantity of heat necessary for dehydration being taken into account. It is claimed that the relative error in the determination of alpha /sub 2/ for the minimum and maximum heat load (q equal to 1700 and 74,200 kcal/m/sup 2/hr, respectively) fell within the range of five to eight%. The determination of optimum hydrodynamic conditions for the boiling of NaOH solutions for required concentrations was performed through a series of experiments, differing in the apparent level of the boiling solution in an oxidized steel tube (diameter 32/38 mm, length 1500 mm). Experiments were conducted under these conditions with the object of determining values of alpha / sub 2/, is the coefficient of heat transfer for boiling solutions of NaOH of various concentrations, and of establishing the dependence of alpha / upon q and the physical properties of the solutions under secondary vapor pressures equal to atmospheric pressure for 5, 10, and 20% solutions, and varying in the range of 0.62 to 0.76 kg/cm/sup 2/ for 15, 30, and 40% solutions. It is claimed (within the range of the parameters of these experiments) that alpha /sub 2/ is proportional to q by the power n plus or minus 0.564 to 0.620. The results obtained are in accord with the data of other authors. In particular, it is emphasized that, with identical heat flow, the coefficients of heat emission to water are greater than to the solution. The quantity alpha /sub 2/ to the solution decreases with increased temperature. Using a special movable thermocouple, the author shows that in the boiling of solutions in a vertical contour with natural circulation, a considerably greater amount of super-heating (~ 2 deg ) takes place than in large-scale boiling. It is pointed out that under optimum conditions the solution is at the greatest temperature, as a rule, at the initial region of the evaporating tube.
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-12-009791
- OSTI ID:
- 4337883
- Journal Information:
- Izvest. Kiev. Politekhn. Inst., Vol. Vol: 17; Other Information: Orig. Receipt Date: 31-DEC-58; Related Information: Translated from Referat. Zhur. Mekh. No. 5, 1957, abstract no. 5703
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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