Optimization Of Thrust Research Articles

Optimization of Thrust of a Generic X-51 Hypersonic Vehicle

A prune-and-search optimization algorithm was combined with a reduced-order model of the scramjet engine within a generic X-51 vehicle. The goal was to maximize the thrust in order to achieve thrust-to-drag ratios that equal or exceed 1, even for the difficult cases of flight at high altitudes and high Mach numbers up to 10. For the inlet to the engine, the lengths and inclination angles of three wall panels were varied. For the combustor, three parameters were varied: the diameter and number of fuel injector ports and the wall divergence angle. These variables affect both the combustion efficiency and the finite-rate chemistry of the surrogate JP-7 fuel. The optimization algorithm showed that at higher flight Mach numbers an inlet that maximizes static pressure ratio is preferred over one that maximizes the stagnation pressure ratio, because good combustion efficiency requires a sufficient static pressure in the combustor. As the flight Mach number is increased, thrust decreases while the drag increases. Thus, it becomes difficult to achieve thrust that exceeds drag. A solution is shown to be increasing the engine inlet area above a critical value that was computed. Advantages of a reduced-order model over a high-fidelity CFD approach are discussed when thousands of computations of all components within an entire engine are required for optimization.

Multiobjective optimization of hydrostatic thrust bearing operating with electrorheological lubricant using Taguchi-fuzzy technique

An electrorheological (ER) fluid falls in the category of a smart lubricant. In an ER lubricant, the dielectric microparticles are suspended in an insulating lubricant like silicon oil. The properties of ER fluids change when they encounter an external electric field. In the present study, the ER lubricant is modeled using a continuous Bingham model. The finite element method is utilized to solve the Reynolds equation to compute fluid film pressure and associated performance indices like load-carrying capacity, stiffness, and damping parameters of hydrostatic thrust bearing. In the present study, the influencing variables, that is, recess shapes, compensating elements, and strength of an electric field have been optimized using the fuzzy-based Taguchi optimization technique. The optimal combination of recess shape, compensating element, and electric field is required to enhance the performance of the hydrostatic thrust bearing. The authors attempt to see the interaction of the input variable by the trade-off study graph. A Taguchi fuzzy-based multipurpose optimization was proposed to optimize the performance indices and an optimal combination of compensating elements, recess shape, and electric field has been presented.

Gas Temperature Distribution in the Combustion Chamber of a GTM400 MOD Turbojet Engine Powered by JET A-1 Fuel and Hydrogen

Research on engine operation using hydrogen may enable appropriate optimization of thrust, and therefore performance, related to its potential use in aircraft. It is particularly important as the share of hydrogen in combustion affects the reduction of combustion products such as carbon dioxide, carbon monoxide, nitrogen oxide, hydrocarbons, and solid matter. This is in line with the new requirements regarding the increased supply of sustainable aviation fuels (SAFs) and the related changes in emissions, i.e., reducing the harmful impact of exhaust gases on the environment. This paper presents the results of measurements carried out in the GTM400 MOD turbojet engine. Based on the research performed, the impact of hydrogen and aviation kerosene combustion on selected engine parameters is presented. The paper shows changes in the rotational speed and volume flow of JET A-1 fuel as a function of engine operation time. Changes in temperature measured at the edge of the flame tube were also examined. The tests confirmed that the combustion chamber worked correctly in the selected area in the range of the tested fuel mixtures. After incorporating hydrogen into the combustion process, the consumption of traditional JET A-1 fuel was significantly reduced.

Structure Optimization of Aerostatic Thrust Bearing Based on Air Film Pressure Field Characteristics Analysis

The air film pressure field (AFPF) of aerostatic thrust bearings significantly determines the working performance of the bearings, and the characteristics of AFPF are closely related to the bearing structure parameters. This study carried out the structure optimization of aerostatic thrust bearing based on the analysis of the AFPF characteristics. The influence law of the number, distribution and the outlet shape of the orifices, as well as the bearing diameter on the static performance of the bearing was investigated. The relationship between bearing structural parameters, AFPF characteristics and bearing static performance was established and effectively used for the structure optimization of aerostatic thrust bearing. The simulation results were verified by the experiment. The results show that the static performance analysis of the aerostatic thrust bearing based on the AFPF characteristics can effectively provide a theoretical basis for the design and optimization of the bearing structure, and improve the bearing performance.

Optimization of Electric Thrust Based on Pulse Arc Plasma Using Pulsed Magnetic Field

Based on the results of a numerical simulation, a possibility in principle is shown to achieve an effective magneto-induction correction of high-gradient plasma expansion from a localized arc source and a respective severalfold increase in the thrust pulse with a steepness of the induction rise in the accelerator on the order of 104 T/s. In these conditions, a pulse-periodic mode of the device operation is required with a delay of the current pulse front in the magnetic field source relative to the ignition voltage pulse in the plasma source, which is determined by the expansion velocity of the plasma cloud within the device.

Design and optimization of permanent magnetic thrust bearing used in vessels

Design and optimization of permanent magnetic thrust bearing used in vessels

Оптимизация электрической тяги на основе импульсной дуговой плазмы с помощью импульсного магнитного поля

Оптимизация электрической тяги на основе импульсной дуговой плазмы с помощью импульсного магнитного поля

Optimization of area ratio and thrust in suddenly expanded flow at supersonic Mach numbers

In this investigation the flow field has been computed by the numerical approach using Computational Fluid Dynamics (CFD) Analysis to investigate the efficacy of the supersonic Mach numbers due to the flow from supersonic nozzle exhausted in a larger circular duct and the corresponding thrust force created due assess the flow development in the circular pipe, its measurement and the magnitude. For this study the nozzles were modeled using academic licensed ANSYS Workbench software. The nozzles were modeled for the Mach numbers 1.5, 2.0 and 2.5. The flow from the nozzles was numerically simulated for nozzle pressure ratios (NPRs) in the range from 2 to 8, and the area ratios of the study were 2, 4, 6, 8 and 10. The simulation results were compared for geometrical and the kinematical parameters. The results indicate that the pressure in the base corner of enlarged duct is influenced by the level of expansion (i.e. Nozzle pressure ratio), inertia level (i.e. Mach number) at the nozzle exit and the relief available (i.e. area ratio) to the shear layer. If the maximum thrust is the aim then the optimum area ratios should be considered. Lower area ratio is not suitable for higher NPR and higher area ratio is not suitable for lower NPR. The higher area ratio provides more space to expand compressed air. Also, the lower area ratio will offer minimum base drag. The base drag is strongly influenced by the area ratio up to certain limit. If the area ratio is again increases then there is no effect of increase in the area ratio on the base drag and Thrust. As the Mach number increases for the same Nozzle pressure ratio and the area ratio, the net thrust force also increases. From the obtained results the optimum area ratio can be selected to maximize thrust for a given Nozzle pressure ratio and Mach number.

Generalized optimization procedure for rotational magnetized direction permanent magnet thrust bearing configuration

Optimization of rotational magnetized direction permanent magnet thrust bearing configuration is carried out using generalized three-dimensional mathematical model. The bearing features namely axial force and stiffness are maximized using in-house developed mathematical expressions solved using MATLAB. The design variables selected for the optimization are axial offset, number of ring pairs, air gap and inner radius of inner and outer rings. The maximized axial force values of the optimized configuration are validated with the finite element analysis results. To overcome the high computational cost associated with three-dimensional equations, generalized method of optimization is sucessfully demonstrated using plots representing variation of optimal design variables as a function of air gap with respect to bearing’s outer diameter. Simple and useful method of using the generalized plots for the process of optimization is presented by dimension optimization of representative bearing configuration with a particular aspect ratio. The proposed optimization using mathematical model and generalized approach assists designer in selecting optimized geometrical parameters of rotational magnetized direction thrust bearing configurations easily for variety of high-speed applications.

Optimization of thrust propeller design for an ROV (Remotely Operated Vehicle) consideration by Genetic Algorithms

Remotely Operated Vehicle (ROV) is one of the technology that can facilitate for observing and exploring the underwater condition (sea). The design and manufacturing process of underwater robots needs many support and increase the performance of the underwater robot to do some missions. Thruster is one of main component which has function as an actuator during the operation. In the present study, propeller design the most important for solving the problem of an ROV. For the optimization of thrust, Genetic Algorithms (GA) can powerfully search for parameters in large multidimensional design space. Thus, the principle can be applied for determining the initial dimension of the propeller for producing optimum thrust of ROV. GA was successfully shown able to obtain an optimal set of parameters leading to propeller characteristics and best performances.

Design, analysis and test of a model turbine blade for a wave basin test of floating wind turbines

Froude scaling is a generally reliable way to design models of floating wind turbines for wave basin testing. However, the resulting rotor thrust of the model is far lower than the Froude-scaled value of a full-size turbine, because the reduction in Reynolds number decreases the lift coefficients and increases the drag coefficients (the Reynolds number scaling effect). A 1/50th scale model wind turbine based on a NREL-5MW reference turbine is examined here. To mitigate the Reynolds number scaling effect in the model, the original aerofoils of the reference turbine (DU series and NACA 64-618) were replaced by an aerofoil at a low Reynolds number (NACA 4412). Such a model with aerofoil-adjusted blades was used in the mathematical optimization of rotor thrust. The design objective was to guarantee that while the rotor thrust of the model equalled the Froude-scaled rotor thrust of the reference, the smallest chord lengths were achieved, considering the weight control in building the model blade. The distribution of chord lengths fitted a fourth-order polynomial curve, and the distribution of twist angles along the blade fitted a second-order polynomial curve. The eight coefficients of the two curves were chosen as optimization variables, and pattern search method was used to solve the optimization model. The model blade was designed at zero pitch angle and further tested in FAST, a fully coupled simulation tool. A model test was conducted using the optimized blade geometry in the State Key Laboratory of Ocean Engineering in Shanghai, China, and the thrusts were compared with the predicted values.

Towards the Capabilities of Rocket Engines with Solar Heating of Working Fluid

The purpose of this research is to show the potentiality of the rocket with solar heating of working fluid. The study describes design of the heater with tungsten pipes, ensuring full-range application of focusing radiation (95 %) under the hydrogen heating to 2900 К; gives an examples of optimization of rocket engine thrust by the flight time with predetermined fuel weight and specific weight of engine with mirror and payload; illustrates design of the engine and mirrors providing the conjugation between the thrust vector and solar radiation vector; demonstrates design of power-supply source with high-efficient solar energy transformation into electric one and compares various types of the rockets.

Optimization of thrust, torque, entry, and exist delamination factor during drilling of CFRP composites

Among variety of fiber-reinforced polymer (FRP) composites, the carbon fiber-reinforced plastics (CFRP) are found to be highly promising materials for widespread applications in aeronautical and aerospace industries. The delamination is a major problem associated with drilling of fiber-reinforced composite materials, which tends to reduce structural integrity of the said material. The problems in drilling, particularly the heterogeneity and anisotropy of composite materials increase delamination. Therefore, drilling of CFRP composites requires adequate attention toward achieving superior hole quality, surface finish, as well as dimensional accuracy by achieving delamination-free machining. However, drilling process is influenced by several machining parameters like drill speed, drill bit diameter, as well as drill material, feed, etc. Direct and interactive effect of aforesaid process variables influences machining performance in terms of quality of the drilled hole. Therefore, an optimal parameter setting is indeed required. To address these issues, present study aims at evaluating an appropriate drilling parameter setting toward optimization of thrust, torque, entry, and exist delamination factor during drilling of CFRP (epoxy) composites. An integrated multiresponse optimization philosophy combining principal component analysis (PCA), fuzzy inference system (FIS), and Taguchi method has been proposed here. The aforesaid optimization module has been found efficient enough to overcome inherent limitations as well as unrealistic assumptions of existing optimization approaches as documented in literature so far.

Analysis and Optimization of Ironless Permanent-Magnet Linear Motor for Improving Thrust

As known, improving launcher thrust is the goal that the mankind is pursuing. There is no saturation phenomenon in the ironless permanent-magnet linear motor (IPMLM); hence, the thrust of IPMLM has a linear relationship with current through windings to provide larger thrust. The topology of IPMLM determines that its thrust fluctuation is smaller than that of an iron permanent-magnet linear motor. In this paper, the model of an air-gap magnetic field is established by the magnetic charge model and the image method for global optimization of IPMLM thrust. All dimensions of IPMLM are described by motor thickness and three ratio coefficients (i.e., α, β , and γ). The cooling power of the cooling system under different temperature gradients, which determines current density of winding, is calculated by Comsol software. Different values of α, β, and γ mean that each dimension of IPMLM is different, the current density in different windings being subject to constraint condition <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cu</sub> ≤ <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> . Therefore, we can obtain the variation of current density with dimension and the variation of thrust with dimension. For obtaining maximum thrust in the same volume, the size ratio among magnetic structure, winding structure, and cooling structure is derived by the thrust analytical expression. The distribution of the IPMLM thermal field is analyzed by a 3-D finite-element method, and this optimization method of IPMLM thrust density is proved by experiment.

Trajectory Optimization of the Exploration of Asteroids Using Swarm Intelligent Algorithms

As a typical NP-HARD problem, trajectory optimization has become the hot point in aerospace research. Considering the limitation of classical optimization algorithms, variant global optimization algorithms for trajectory optimization are applied in an extensive literature. Based on the parameter optimization of low thrust and impulse maneuver, this paper investigates the difference evolution (DE), particle swarm optimization (PSO), and genetic algorithm (GA) algorithms and generates two hybrid algorithms. DE proves to be superior to other non-hybrid algorithms in trajectory optimization problems. The hybrid algorithm of PSO and DE can improve the optimization performance of DE, which is validated by two given benchmarks. The results in this paper indicate the validity and feasibility of the hybrid algorithms.

MC-38 Development of a Low-profile, Small-diameter HDD Motor for Mobile Applications

A low-profile, small-diameter HDD motor for mobile application with fluid dynamic bearing had been developed. The thickness between the bottom of the motor and the top of the disk is 1.9mm. Although the radial bearing length is rather short, disk axial vibration can be reduced with optimization of thrust bearing structure. Magnetic noise from motor to head can be reduced with thin shield plate.

Stiffness optimization of a variable restrictor-compensated hydrostatic thrust bearing system

In hydrostatic bearing systems, proper matching of the parameters of the compensating restrictor to those of the bearing is important. Optimum values of the variable parameters of the bearing system for maximum stiffness have been obtained by the steepest gradient method of optimization for circular and rectangular pads. The analysis provides an optimum configuration of the bearing restrictor system.