Abstract
An innovative variant of a multiphase marine ramjet is investigated analytically and experimentally. Pressure liquefied gas (LG) is injected, boiling under superheat conditions in the water stream within the propulsion unit, and serving as an on-board bubble source necessary for the ramjet operation. Experiments were conducted in a 10 m diameter tow pool at a speed range of 7–18 m/s (approximately 14–35 knots). For the laboratory concept demonstration and process characterization, two liquefied gases, butane and R134a (synthetic refrigerant gas), were employed. In practical applications, non-polluting LGs such as liquid air may be used. The results reveal the overall performance comparable to the operation with pressurized air, with some thrust advantage of the LG at high-speed tests, attributed to the volume increase of gas during phase change, in accordance with the thermodynamic power cycle analysis.
Highlights
The marine ramjet (MRJ) is the nautical equivalent of the aeronautical ramjet, using water instead of air as the main working fluid
Different concepts for marine ramjet propulsion are summarized by Gany [1]
In the case of the marine ramjet type investigated in this research, energy is added not in the form of fuel combustion or chemical reaction but by introducing a secondary gaseous fluid, reducing the mean density of the flow, making it compressible, the secondary and adding its expansion work. fluid is traditionally compressed aWir h(mileastshfleomwairnatfleum.ida).isTwheapterres(emnatssstufldoywforcautes,ems. own), the replacement of the compressed air with an on-board pressure liquefied gas
Summary
The marine ramjet (MRJ) is the nautical equivalent of the aeronautical ramjet, using water instead of air as the main working fluid. In both cases, the incoming ambient fluid enters the propulsor due to the motion of the vehicle, without using means such as pumps or compressors. In the case of the marine ramjet type investigated in this research, energy is added not in the form of fuel combustion or chemical reaction but by introducing a secondary gaseous fluid, reducing the mean density of the flow, making it compressible, the secondary and adding its expansion work. Own), the replacement of the compressed air with an on-board pressure liquefied gas
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