Water jet thruster, which is a marine system that creates a jet of water for propulsion, has several advantages such as low noise, good anti-cavitation characteristics and maneuvering characteristics. The reaction thr...Water jet thruster, which is a marine system that creates a jet of water for propulsion, has several advantages such as low noise, good anti-cavitation characteristics and maneuvering characteristics. The reaction thrust characteristics of water jet for conical nozzles directly determine the speed of autonomous underwater vehicles （AUV）. Theoretical, numerical and experimental studies have been, carried out to investigate the effects of the nozzle geometries as well as inlet conditions on the reaction thrust of water jet in this paper. The experimental results show that： 1） the reaction thrust is proportional to inlet pressure, the square of flow rate and 2/3 power exponent of input power; 2） the diameter of cylinder column for conical nozzle has great influence on the reaction thrust characteristics; 3） the best values of the half cone angle and the cylinder column length exist to make the reaction thrust coefficient to reach the maximum under the same inlet conditions. Those provide a basis for nozzles design and have significant value, especially for developing high performance and efficiency water jet propulsion unit.展开更多
Clear knowledge on the reaction thrust of water jet is valuable for better design of water jet propulsion system. In this paper, theoretical, numerical and experimental studies were carried out to investigate the effe...Clear knowledge on the reaction thrust of water jet is valuable for better design of water jet propulsion system. In this paper, theoretical, numerical and experimental studies were carried out to investigate the effects of the nozzle geometry as-well as the inlet conditions on the reaction thrust of water jet. Comparison analyses reveal that the reaction thrust has a direct proportional relationship with the product of the inlet pressure, the square of flow rate and two-thirds power exponent of the input power. The results also indicate that the diameter of the cylinder column for the conical nozzle has great influence on the reaction thrust characteristics. In addition, the best values of the half cone angle and the cylinder column length exist to make the reaction thrust reach its maximum under the same inlet conditions.展开更多
The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. T...The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. The simulation of the flow field characteristics was conducted via the FLUENT computational fluid dynamics package. Effects of the inlet conditions and the nozzle dimensions on the reaction thrust of a water jet were addressed particularly. The reaction thrust experiments were performed on a custom-designed test apparatus. The experimental results reveal that a） the nozzle diameter and the inlet conditions exert great influence on the water jet reaction thrust; and b） for L≤4d0, where the nozzle is treated as a thin plate-orifice, the reaction thrust is independent of nozzle length; for L〉4d0, where the nozzle is treated as a long orifice, the reaction thrust can reach maximum under the condition of a certain flow rate. These findings lay a theoretical foundation for the design of nozzles and have significant value, especially for the future development of high-oressure water-let orooulsion technology.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.50775081)the National High Technology Research and Development Program of China(863 Program,Grant No.2006AA09Z238)
文摘Water jet thruster, which is a marine system that creates a jet of water for propulsion, has several advantages such as low noise, good anti-cavitation characteristics and maneuvering characteristics. The reaction thrust characteristics of water jet for conical nozzles directly determine the speed of autonomous underwater vehicles （AUV）. Theoretical, numerical and experimental studies have been, carried out to investigate the effects of the nozzle geometries as well as inlet conditions on the reaction thrust of water jet in this paper. The experimental results show that： 1） the reaction thrust is proportional to inlet pressure, the square of flow rate and 2/3 power exponent of input power; 2） the diameter of cylinder column for conical nozzle has great influence on the reaction thrust characteristics; 3） the best values of the half cone angle and the cylinder column length exist to make the reaction thrust coefficient to reach the maximum under the same inlet conditions. Those provide a basis for nozzles design and have significant value, especially for developing high performance and efficiency water jet propulsion unit.
基金supported by the National Natural Science Foundation of China (Grant No.50375056)the National High-Technology Research and Development Program of China (Grant No.2006AA09Z238)
文摘Clear knowledge on the reaction thrust of water jet is valuable for better design of water jet propulsion system. In this paper, theoretical, numerical and experimental studies were carried out to investigate the effects of the nozzle geometry as-well as the inlet conditions on the reaction thrust of water jet. Comparison analyses reveal that the reaction thrust has a direct proportional relationship with the product of the inlet pressure, the square of flow rate and two-thirds power exponent of the input power. The results also indicate that the diameter of the cylinder column for the conical nozzle has great influence on the reaction thrust characteristics. In addition, the best values of the half cone angle and the cylinder column length exist to make the reaction thrust reach its maximum under the same inlet conditions.
基金Funded by the Natural Science Foundation of China (No. 50775081)the National High-tech R&D (863) Program No. 2006AA09Z238)the NCET-07-0330, State Education Ministry.
文摘The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. The simulation of the flow field characteristics was conducted via the FLUENT computational fluid dynamics package. Effects of the inlet conditions and the nozzle dimensions on the reaction thrust of a water jet were addressed particularly. The reaction thrust experiments were performed on a custom-designed test apparatus. The experimental results reveal that a） the nozzle diameter and the inlet conditions exert great influence on the water jet reaction thrust; and b） for L≤4d0, where the nozzle is treated as a thin plate-orifice, the reaction thrust is independent of nozzle length; for L〉4d0, where the nozzle is treated as a long orifice, the reaction thrust can reach maximum under the condition of a certain flow rate. These findings lay a theoretical foundation for the design of nozzles and have significant value, especially for the future development of high-oressure water-let orooulsion technology.
