Linear model of the electrogasdynamic characteristics of the dry electrostatic cooling nozzle

A brief review of the essence and physical mechanisms of dry electrostatic cooling technology is presented, the areas of application of this technology are described and the main aspects which hamper its wide use are formulated, in particular the insufficient theoretical study of the issue of determining the main electrogasdynamic parameters of the nozzle of the dry electrostatic cooling unit while designing technological operations. The maximum electric voltage, ensuring stable corona discharge in the nozzle of the unit without transition to spark discharge - pre-spark voltage - was accepted as the main indicator of effective functioning of the unit of dry electrostatic cooling. Experiments were performed to study the impact of nozzle diameter and air pressure on the pre-spark voltage. In the course of the experiments a linear dependence of the pre-spark voltage on the nozzle diameter was found. It was also found that there is a constant for all diameters of stabilization air pressure, above which the pre-spark voltage does not change significantly. Experiments were carried out to study the impact of nozzle needle offset on the pre-spark voltage at an air pressure equal to the stabilization pressure. As a result of the experiments, the limit offset of the needle ensuring stable functioning of the dry electrostatic cooling unit was found. The parameter of nozzle geometry - modified diameter - is proposed. This parameter integrates the nozzle diameter and the needle offset. Using the modified diameter, an easy-to-use linear dependence between the studied parameters is obtained.