Hydrodynamics and Thermal Interaction with Air at Water Jet Blow Against Its Surface in the Limited Volume with Scattering of the Received Drops

Ivan I. Pukhovyi

Abstract


Background. Air heating in winter in the range of ambient temperatures below -5°С is possible with heat of the phase transition of water into ice. Heated air reduces the energy consumption in ventilation systems and air–water and air–air heat pumps during peak loads on the heating system reducing the installed capacity of the heat generating equipment. For water cooling and nozzle irrigation the water should be dispersed into droplets, and through contact with fast airflow drops shouldn’t be carried away by the flow, that is achieved by increasing the diameter of drops.

Objective. The aim of the paper is determination of parameters of jet flowing and crushing on drops and evaluation of the maximum radius of droplet flight depending on the geometric characteristics of the vessels (diameter and depth) and the water flow through the nozzle from which the jet emerges. It is also planned to study the possibility of heating and cooling water with air sucked by the jet.

Methods. The air temperature below -5°С is heated in the conditions of forced flow with no entrainment of droplets by a jet. The lower the air temperature, the greater the economic and energy effect.

Results. We experimentally investigated the destruction processes of the water jet on the primary drop with the definition of the jet destruction beginning and the diameter of primary drops. Moreover, we have carried out experimental studies on the dependence of the maximum radii of the secondary droplets from the destruction of air bubbles formed by the water jet impact on the water surface saturated with air, depending on the diameters and heights of the water vessels.

Conclusions. It was found that the decrease in the diameter of the vessels and the liquid layer, as well as the increase in the water flow through the nozzle, contribute to the drop spread to large radii. From a physical point of view, this effect should be explained by a smaller loss of jet energy with an increase of the horizontal and vertical dimensions of the vessel and an increase of air pressure in the bubbles.

Keywords


Hydrodynamics; Thermal interaction; Flight radius; Flow parameters; Jet energy

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DOI: https://doi.org/10.20535/1810-0546.2018.2.128966

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