THEORETICAL METHOD OF THE OPTIMUM DESIGN OF A SUPERCAVITATING PROPELLER BLADE WITH SPOILER MOUNTED ON THE TRAILING EDGE

2021 ◽  
Vol 152 (A1) ◽  
Author(s):  
Zaw Win ◽  
G M Fridman ◽  
A S Achkinadze
Keyword(s):  
Design Method ◽  
Theoretical Method ◽  
Blade Design ◽  
Propeller Blade ◽  
Trailing Edge ◽  
Theoretical Design ◽  
Closure Scheme ◽  
Blade Section ◽  
Cavity Closure ◽  
Cfd Method

This paper presents theoretical design method to obtain 2-D optimum section with spoiler mounted on the trailing edge of a supercavitating propeller blade. Matched Asymptotic Expansions (MAE) is applied to determine the geometry of profile and cavity shape in the framework of potential flow theory. The blade section is of wedge-like shape and the opened cavity closure scheme is adopted. A typical section, on which the optimum blade design will be based, is singled out among the best individual sections from root to tip. The spoiler length of each hydrofoil section resulting from MAE method are finalized with CFD method so as to consider viscous effect under the same lift condition, others hydrofoil geometries being kept constant. The hydrodynamic performances of all blade sections being designed on the basis of the resulting typical section from linearized method are finally predicted with CFD method.

The Aerodynamics of a Turbine Cascade With Supersonic Discharge and Trailing Edge Blowing

1974 ◽  
Author(s):  
I. P. MacMartin ◽  
J. F. Norbury
Keyword(s):  
Total Pressure ◽  
Design Method ◽  
Turbine Cascade ◽  
Trailing Edge ◽  
Trailing Edges ◽  
Blade Section ◽  
Cooling Air Flow ◽  
Improved Model ◽  
Cooling Air ◽  
Theoretical Considerations

This paper presents a very thorough experimental investigation of a supersonic turbine cascade with thick trailing edges designed for trailing edge ejection of cooling air. Experiments were performed on a supersonic turbine cascade designed for a deflection of 135 deg and outlet Mach number 1.2. The blade section was designed for high rates of cooling air flow, the cooling air being ejected through a slot in a relatively thick trailing edge. Results were obtained for both the blown cascade and the equivalent cascade with solid trailing edges. The flow was found to be substantially different from that assumed in the design method, the effect of reduced base pressure at the trailing edges being especially important. Theoretical considerations lead to an improved model of the flow and in particular the high total pressure loss measured experimentally is largely explained.

scholarly journals Blade Section Profile Array Lifting Surface Design Method for Marine Screw Propeller Blade

2019 ◽  
Vol 26 (4) ◽  
pp. 134-141
Author(s):  
Przemysław Król
Keyword(s):  
Design Method ◽  
Main Idea ◽  
Surface Model ◽  
Propeller Blade ◽  
Surface Design ◽  
Propeller Design ◽  
Lifting Surface ◽  
Screw Propeller ◽  
Blade Section ◽  
Circulation Distribution

Abstract The lifting surface model is widely used in screw propeller design and analysis applications. It serves as a reliable tool for determination of the propeller blade mean line and pitch distribution. The main idea of this application was to determine the blade shape that would satisfy the kinematic boundary condition on its surface with the prescribed bound circulation distribution over it. In this paper a simplified lifting surface method is presented – in which the 3D task for the entire blade is replaced by a set of 2D tasks for subsequent blade section profiles.

scholarly journals CFD simulation of flapped rotors

2015 ◽  
Vol 119 (1222) ◽  
pp. 1561-1583 ◽  
Author(s):  
F. Dehaeze ◽  
K. D. Baverstock ◽  
G. N. Barakos
Keyword(s):  
Cfd Simulation ◽  
Blade Design ◽  
Trailing Edge ◽  
Moment Coefficient ◽  
Trailing Edge Flaps ◽  
Negative Damping ◽  
The Moment ◽  
Cfd Method ◽  
Noise And Vibration Reduction ◽  
High Thrust

AbstractThe use of active trailing edge flaps on rotors may lead to performance benefits as well as noise and vibration reduction. In this work, computational fluid dynamics, using the HMB2 solver, is used to assess the effect of the trailing edge flaps on the whole flight domain of a modern main rotor. Starting from a baseline blade design, multiple techniques are demonstrated. The flap is first assessed using 2D pitching aerofoil simulations, followed by dMdt simulations, that account for the simultaneous variations of pitch and Mach around the azimuth. It was shown that enhanced lift was obtained while inspection of the moment coefficient showed negative damping for the flap for a limited set of conditions. Due to the 2D formulation, dMdt computations are fast to perform and can be used to inform codes predicting the rotor performance. The flap was then assessed in hover, and only allowed for limited improvement in blade performance at high thrust. In forward flight, the flap was actuated at a frequency of 1 per revolution, and was found to have a strong effect on the loads on the retreating side. The effect on the moments was even stronger. The flight envelope of the blade was explored, and clean and flapped cases were compared. The most noticeable changes occur at high and medium thrust. The CFD method was found to be efficient and robust, without any substantial penalties in CPU time, due to the flap modelling, over the tested conditions.

Pure Design Method for Aerofoils in Cascade

1969 ◽  
Vol 11 (5) ◽  
pp. 454-467 ◽  
Author(s):  
K. Murugesan ◽  
J. W. Railly
Keyword(s):  
Exact Solution ◽  
Velocity Distribution ◽  
Design Problem ◽  
Design Method ◽  
Tangential Velocity ◽  
Surface Velocity ◽  
Normal Velocity ◽  
Blade Design ◽  
Blade Shape

An extension of Martensen's method is described which permits an exact solution of the inverse or blade design problem. An equation is derived for the normal velocity distributed about a given contour when a given tangential velocity is imposed about the contour and from this normal velocity an initial arbitrarily chosen blade shape may be successively modified until a blade is found having a desired surface velocity distribution. Five examples of the method are given.

scholarly journals Quadratic feedback–based equivalent sliding mode control of wind turbine blade section based on rigid trailing-edge flap

2019 ◽  
Vol 52 (1-2) ◽  
pp. 81-90 ◽  
Author(s):  
Ting-Rui Liu
Keyword(s):  
Sliding Mode Control ◽  
Wind Turbine ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Trailing Edge ◽  
Feedback Parameter ◽  
Flutter Suppression ◽  
Mode Control ◽  
Blade Section ◽  
Trailing Edge Flap

Modeling of aeroelastic system of wind turbine blade section based on chordwise rigid trailing-edge flap has been investigated. The flutter suppression of blade section exhibiting flap-wise bending and twist deformation is performed by equivalent sliding mode control. Aerodynamic expressions are based on the modified quasi-steady model which is attached to the influences of trailing-edge flap. The continuous equivalent sliding mode control algorithm based on quadratic feedback parameter is applied to realize flutter suppression, with displacements and velocities, control input of angle of trailing-edge flap and sliding mode function demonstrated. To facilitate the process of computer implementation, the discrete equivalent sliding mode control algorithm is discussed in detail, with better control effects and angle control of trailing-edge flap demonstrated. The quadratic feedback–based equivalent sliding mode control algorithm, including continuous equivalent sliding mode control and discrete equivalent sliding mode control, realizes the analysis of control effects based on feedback parameter with empirical adjustment coefficient. This provides schemes of not only theoretical simulation but also real-time implementation for the application of equivalent sliding mode control in different engineering projects.

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