Title: Experiment and Numerical Calculation on Air-Water Phased Propulsion Flow of Water Rocket
Abstract: Water rocket is propelled by ejecting water using pressurized air. When the quantity of water decreases, the water and the air are ejected simultaneously in two phased flow. Experimental and numerical studies of this kind of air-water phased ejection are few .Therefore it is not yet completely clear about the flow and thrust generation characteristics. In this study, a measurement equipment was prepared to obtain the time history of air-water propulsive characteristics. Photos of air-water phased propulsion flow were also taken using a high-speed digital video camera to examine the thrust generation mechanism. A recent paper reported that a fully disturbed and mixed air-water phased flow is established at about 0.3 seconds after water ejection start. But the present experiment tells us that an air column grows from the upper surface of water to penetrate the nozzle flow. This air-water phased nozzle flow is not fully disturbed as reported previously, but is clearly separated into the air column flow and the cylindrical water flow. A whirl airflow may occur in a certain water amount and air pressure condition. Typical flow parameters are obtained to find that the air column penetrates faster than the water ejection. Numerical calculations are conducted to clarify the air-water phased flow characteristics. The growth of the air column is well simulated as the experiment.
Publication Year: 2008
Publication Date: 2008-11-01
Language: en
Type: article
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