Evaluation of Aerodynamic and Stability Performance Parameters of High Wing Piston Engine Aircraft

The purpose of this paper is to numerically study the effect of texture bottom profile on static, dynamic, and stability performance parameters of hydrodynamic journal bearings. The different performance parameters of square textured journal bearings with different bottom profiles are numerically investigated and compared with those of smooth journal bearing. There are five bottom profiles of this square texture: flat, curved, isosceles triangle (T1), oblique triangle (T2), and oblique triangle (T3). The static and dynamic coefficients are calculated by solving the steady-state Reynolds equation and the perturbation equations with FDM numerical technique. The performance characteristics under different texture distribution, depth, and bottom profiles are studied, and the current numerical results show that the selection of texture parameters is crucial to improve the static, dynamic, and stability performances of hydrodynamic journal bearing. Meanwhile, it is also found that the square texture with a flat bottom profile has a higher improvement in the values of static performance parameters in comparison to those other bottom profiles. Moreover, the simulation results indicate that the dynamic and stability performances improvement of textured journal bearing is also significant, especially when the eccentricity ratio is smaller.

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Possibility-Based Multidisciplinary Optimisation For Electric-Powered Unmanned Aerial Vehicle Design

The Aeronautical Journal ◽

10.1017/s0001924000011313 ◽

2015 ◽

Vol 119 (1221) ◽

pp. 1397-1414 ◽

Cited By ~ 9

Author(s):

N. V. Nguyen ◽

J.-W. Lee ◽

M. Tyan ◽

D. Lee

Keyword(s):

Design Space ◽

Point Of View ◽

Vehicle Design ◽

High Fidelity ◽

Performance Parameters ◽

Piston Engine ◽

Design Variables ◽

Aerial Vehicle ◽

And Performance ◽

System Point

AbstractThis paper describes a possibility-based multidisciplinary optimisation for electric-powered unmanned aerial vehicles (UAVs) design. An in-house integrated UAV (iUAV) analysis program that uses an electric-powered motor was developed and validated by a Predator A configuration for aerodynamics, weight, and performance parameters. An electric-powered propulsion system was proposed to replace a piston engine and fuel with an electric motor, power controllers, and battery from an eco-system point of view. Moreover, an in-house Possibility-Based Design Optimisation (iPBDO) solver was researched and developed to effectively handle uncertainty variables and parameters and to further shift constraints into a feasible design space. A sensitivity analysis was performed to reduce the dimensions of design variables and the computational load during the iPBDO process. Maximising the electric-powered UAV endurance while solving the iPBDO yields more conservative, but more reliable, optimal UAV configuration results than the traditional deterministic optimisation approach. A high fidelity analysis was used to demonstrate the effectiveness of the process by verifying the accuracy of the optimal electric-powered UAV configuration at two possibility index values and a baseline.

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Simulation of the Performance of a Twin-Rotor Piston Engine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.376.360 ◽

2013 ◽

Vol 376 ◽

pp. 360-365

Author(s):

Teng An Zou ◽

Cun Yun Pan ◽

Hai Jun Xu ◽

Xiang Zhang

Keyword(s):

Engine Performance ◽

Analytical Tool ◽

Chamber Pressure ◽

Preliminary Design ◽

Performance Parameters ◽

Piston Engine ◽

Working Cycle ◽

The Given ◽

Twin Rotor ◽

Engine Cycle

A comprehensive computer simulation has been developed to predict the performance of a twin-rotor piston engine (TRPE) by means of the zero-dimensional thermodynamic model. With the given model, the chamber mass, pressure and temperature are available during a complete engine cycle. The results are consistent with the TRPE’s working cycle trend. By the chamber pressure, the overall engine performance parameters can be calculated. The model can be used as an analytical tool for preliminary design and development of the TRPE.

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Influence of texture geometries on the performance parameters of hydrodynamic journal bearing

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650120982691 ◽

2021 ◽

pp. 135065012098269

Author(s):

Niranjan Singh ◽

Rajeev Kumar Awasthi

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Aspect Ratio ◽

Journal Bearing ◽

Geometric Parameters ◽

Performance Parameters ◽

Surface Textures ◽

Stability Performance ◽

Hydrodynamic Journal Bearing ◽

Bearing System

The operating and geometric parameters of textures affect the static, dynamic, and stability performance characteristics of a journal-bearing system. The present work investigates the influence of spherical-, cylindrical-, triangular-, and kite-shaped textures on the performance parameters of a journal-bearing system. The flow of a lubricant is assumed to be Newtonian and iso-viscous. Reynold's equation governing the flow of a lubricant between the space in the bearing and the journal is solved by a finite-element method. The computed results indicate that the spherically textured journal bearing provides better improvement in the performance parameters vis-a-vis other textured bearings. In general, the effect of texture shapes is more pronounced at the aspect ratio of surface textures is 1.0.

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