Transient analysis of the influence of gap size of the rotor from stator on hydrodynamic performance of the linear jet propulsion system

Linear Jet system which has a stator in addition to a rotor combines the best elements of two existing technologies of conventional screw propellers and water jets. In designing this propulsion system, tip clearance plays an essential role, since it causes the appearance of tip vortex that leads to a further loss in efficiency and a probability of cavitation phenomenon. Due to lack of any study in this regard, it is thus necessary to study tip clearance to find the appropriate geometry for linear jet propulsion system. In the current paper, hydrodynamic performance of linear jet propulsion system is numerically investigated. Accordingly, Ansys-CFX software is utilized and RANS unsteady equations are solved using SST turbulent model. Results of the proposed numerical model, in the form of thrust and torque coefficient as well as efficiency, are compared with available experimental data for a ducted propeller. It is concluded that most of the errors at various advance ratios for thrust and torque coefficients are less than 3% and relatively good agreement is observed. Hydrodynamic investigation involves five different sizes of tip clearance (2.5 to 10% of the rotor diameter). Simulation results indicate that thrust and torque coefficients decreases about 10% and 8% respectively, at the same advance coefficient (J) with an increase in tip clearance. Effects of tip clearance on tip-separation vortex and tip leakage vortex are also examined. At about 20% of chord length from the leading edge, separation occurs. As tip clearance size increases, the tip-leakage vortex also increases. At different advance ratios and higher tip clearance, an increase in vortex and a sudden decrease in thrust is generated by the propeller. By changing the time about 0.8 of the rotor periods, the evolution of the vortex generation behind the rotor at the tip of the blade is clearly observed.

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Utilization of Open-Source OpenFOAM Code to Examine the Hydrodynamic Characteristics of a Linear Jet Propulsion System with or without Stator in Bollard Pull Condition

International Journal of Rotating Machinery ◽

10.1155/2020/8867416 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11

Author(s):

Parviz Ghadimi ◽

Negin Donyavizadeh ◽

Pouria Taghikhani

Keyword(s):

High Speed ◽

Water Jet ◽

Propulsion System ◽

Hydrodynamic Performance ◽

Hydrodynamic Characteristics ◽

Propulsion Systems ◽

Thrust Coefficient ◽

Jet Propulsion ◽

Marine Industry ◽

Total Thrust

With the development of high-speed crafts, new propulsion systems are introduced into the marine industry. One of the new propulsion systems is linear jet which is similar to pump jet and has a rotor, a stator, and a duct. The main difference between this system and pump jet is the placement of linear jet system under the hull body and inside a tunnel. Since this system, like a water jet, is inside the tunnel, the design idea of this system is a combination of a water jet and pump jet. In this paper, hydrodynamic performance of linear jet propulsion system is numerically investigated. To this end, the OpenFOAM software is utilized and RANS steady equations are solved using a k - ε turbulent model. The linear jet geometry is produced by assembling a Kaplan rotor, stator with a NACA 5505 cross section, and a decelerating duct. The results of numerical solution in the form of thrust, torque coefficient, and efficiency are compared with available experimental data for a ducted propeller, and good agreement is displayed. Subsequently, the hydrodynamic parameters are computed in two conditions: with a stator and without a stator. By comparing the results, it is observed that the total thrust coefficient of the propulsion system with a stator at all advance ratios increases by at least 40%. It is further observed that addition of a stator also improves its efficiency.

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Efficacy Analysis of Thickness and Camber Size of Cross Section of the Stator on Hydrodynamic Parameters in Linear Jet Propulsion System

Mathematical Problems in Engineering ◽

10.1155/2020/5861948 ◽

2020 ◽

Vol 2020 ◽

pp. 1-17 ◽

Cited By ~ 1

Author(s):

Negin Donyavizadeh ◽

Parviz Ghadimi

Keyword(s):

Cross Section ◽

High Speed ◽

Pressure Coefficient ◽

Propulsion System ◽

Hydrodynamic Performance ◽

Foil Thickness ◽

Jet Propulsion ◽

Efficacy Analysis ◽

Ansys Cfx ◽

Thrust And Torque

The linear jet propulsion system, unlike pump-jets which are widely used in underwater bodies, is installed inside a tunnel under the vessel and can be used for high-speed crafts, tugs, and service boats. However, this system has not received adequate attention by researchers, which is the subject of the current study. In the present paper, hydrodynamic performance of the linear jet propulsion system is numerically investigated. Accordingly, the Ansys-CFX software is utilized and RANS equations are solved using the SST turbulent model. The results of the proposed numerical model, in the form of thrust and torque coefficient as well as efficiency, are compared with available experimental data for a ducted propeller, and good compliance is achieved. Considering the importance of stator cross section on the performance of the linear jet propulsion system, the influence of thickness and camber size of the stator on linear jet propulsion systems are examined. Based on the numerical findings, it is determined that at constant advance ratio, with increasing thickness of stator, the efficiency increases. It is also observed that as the span length increases, the maximum and minimum of the pressure coefficient increase for different thicknesses. Furthermore, it is seen that positive and negative pressure coefficients decrease with an increase in foil thickness.

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Fairey Jet Propulsion System: Intermittent Firing System Patented

Astronautics ◽

10.2514/8.10367 ◽

1943 ◽

Vol 13 (55) ◽

pp. 10-10

Keyword(s):

Propulsion System ◽

Jet Propulsion ◽

Firing System

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Research on Hydrodynamic Performance of Hybrid Propulsion System

10.3940/rina.wp.2008.07 ◽

2008 ◽

Author(s):

C Sun ◽

◽

Y Wang ◽

Z Li ◽

◽

...

Keyword(s):

Propulsion System ◽

Hydrodynamic Performance ◽

Hybrid Propulsion

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Some Stability and Control Aspects of Airframe/Propulsion System Interactions on the YF-12 Airplane

Journal of Engineering for Industry ◽

10.1115/1.3438447 ◽

1974 ◽

Vol 96 (3) ◽

pp. 820-826 ◽

Cited By ~ 2

Author(s):

D. T. Berry ◽

G. B. Gilyard

Keyword(s):

Static Stability ◽

Propulsion System ◽

Jet Propulsion ◽

Stability And Control ◽

The Stability ◽

And Control ◽

Large Aircraft

Airframe/propulsion system interactions can strongly affect the stability and control of supersonic cruise aircraft. These interactions generate forces and moments similar in magnitude to those produced by the aerodynamic controls, and can cause significant changes in vehicle damping and static stability. This in turn can lead to large aircraft excursions or high pilot workload, or both. For optimum integration of an airframe and its jet propulsion system, these phenomena may have to be taken into account.

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The Design of Water-Jet Propulsion Systems for Hydrofoil Craft

Marine Technology and SNAME News ◽

10.5957/mt1.1965.2.1.15 ◽

1965 ◽

Vol 2 (01) ◽

pp. 15-25

Author(s):

Joseph Levy

Keyword(s):

Water Jet ◽

Propulsion System ◽

Specific Design ◽

Propulsion Systems ◽

Propulsive Efficiency ◽

Jet Propulsion ◽

Performance Curves

This paper contains a brief description of the water-jet propulsion system as applied to hydrofoil craft, and a discussion of the salient hydrodynamic aspects of the problem of fitting the main propulsion system to the specified thrust-versus-speed requirements. The factors that affect the overall propulsive efficiency and the weight of the system are discussed at some length; procedures for optimization of performance at the design cruising speed are outlined; finally, the processes by which the performance at off-design conditions may be evaluated are discussed and illustrated with performance curves for one specific design.

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