Amount Of Thrust Research Articles

Numerical investigation and performance comparison of UAV propeller with varying duct configuration

PurposeThe purpose of this study is to investigate the effects of propeller thrust with two different duct configurations. Propellers in a quadcopter play an indispensable role in generating the necessary thrust and torque to keep the drone flying and manoeuvring. Based on the specific purpose of the unmanned aerial vehicle, both the altitude and attitude can be varied by the amount of thrust produced.Design/methodology/approachThis paper deals with the generation of three numerical models such as plain rotor, rotor with fixed duct and rotor with rotating duct and the comparison of their amount of generated thrust. The plain rotor numerical analysis was compared with the experimental results. The rotor taken for the analysis was 15 mm*5.5 mm TAROT 650. Thrust was measured for all models at four different angular speeds, such as 2,500 rpm, 4,000 rpm, 5,500 rpm and 7,000 rpm.FindingsDue to the suction pressure gradient on the duct inlet surface, the additional amount of lift is produced, and it is the best way of increasing propulsion efficiency and its aerodynamic performance as it reduces the tip loss at the tip of the propeller. The turbulence model taken for the numerical analysis was k−ε.Originality/valueThe rotating duct is expected to provide additional thrust by the increased upward force due to the rotation of duct. The rotating duct produced the optimal results between the plain model and ducted model. At the highest speed of 7,000 rpm, the ducted propeller produced 24.97 N, and the rotating duct propeller produced 23.89 N, whereas the plain propeller produced 23 N thrust. Nearly 8.6% of the thrust improvement is observed in duct and 3.87% in rotating duct.

Numerical simulation of optimizing the swing curve of a 3DOF biomimetic pectoral fin in drag mode

In response to the optimization problem of the motion law of the pectoral fins of biomimetic robotic fish, this paper uses computational fluid dynamics (CFD) methods to achieve the CFD optimization of two types of rigid biomimetic pectoral fins with three degrees of freedom (DOF): elliptical and 8-shaped swing curves. By analyzing the hydrodynamic characteristic curve of the pectoral fins, pressure distribution upstream and downstream of the fin surface, velocity vector of the surrounding flow field during pectoral fin swing, and three-dimensional vortex structure, it is found that when the pectoral fins are pushed forward in an elliptical swing curve, the resistance peak value decreases after two optimizations. However, at the same time, a certain amount of thrust is lost. When the pectoral fin advances in an 8-shaped swinging curve, after two optimizations, the pectoral fins resistance decreases while maintaining an enormous thrust, comprehensively improving the propulsive effect of the pectoral fin on the robotic fish. By substituting the optimized 8-shaped pattern into the robotic fish model, it is found that the flapping angle of 35° has better drag reduction performance, and the average swimming speed of the robotic fish is the fastest at this angle.

Penerapan Hukum Newton dalam Menghitung Sudut Efektif pada Gerakan Bench Press

Bench press is a form of powerlifting exercise that aims to increase the strength and endurance of the muscles of the upper body, that is, the muscles of the chest, arms, and shoulders. The characteristic of the bench press exercise is to lift or push the weight using both hands in a supine position. The purpose of this research is to determine the effective angle required for lifting weights with the least amount of thrust (biomechanics aspects). The research steps were carried out in four stages, namely: first, designing biomechanics mathematical equations; second, experiments on people doing bench press movements; third, processing biomechanics data; and fourth, analysis and discussion of biomechanics data. According to the study's findings, an effective angle was obtained by analyzing the thrust to lift the barbell, that is, the angle flanked by the upper and lower arms, which is approximately 89°-114° for those who use the smallest thrusts on the grip: 0.4 m, 0.5 m, and 0.6 m. It can be concluded that the wider the distance between the grips, the greater the thrust required.

Development of a Multi-Segment Parallel Compressor Model for a Boundary Layer Ingesting Fuselage Fan Stage

The present methodological study aims to assess boundary layer ingestion (BLI) as a promising method to improve propulsion efficiency. BLI utilizes the low momentum inflow of the wing or fuselage boundary layer for thrust generation in order to minimize the required propulsive power for a given amount of thrust for wing or fuselage-embedded engines. A multi-segment parallel compressor model (PCM) is developed to calculate the power saving from full annular BLI as occurring at a fuselage tail center-mounted aircraft engine, employing radially subdivided fan characteristics. Applying this methodology, adverse effects on the fan performance due to varying inlet distortions depending on flight operating point as well as upstream boundary layer suction can be taken into account. This marks one step onto a further segmented PCM model for general cases of BLI-induced inlet distortion and allows the evaluation of synergies between combined BLI and active laminar flow control as a drag reduction measure. This study, therefore, presents one further step towards lower fuel consumption and, hence, a lower environmental impact of future transport aircraft.

On Cathode Position and Inclination Angle in Magnetically Shielded Hall Thrusters

This study systematically investigated the influence of the position and inclination angle of an externally mounted hollow cathode in 1.35 kW magnetically shielded Hall thrusters to establish the relationship between thruster performance, plume state, and cathode placement. For this purpose, a combined motor driver with a three-degree-of-freedom movement was designed to move the cathode over a wide range of positions and inclination angles. In an experiment performed on a thruster with outer magnetic columns, placing the cathode inside the magnetic separatrix resulted in a considerable amount of thrust. However, an extremely small distance between the cathode and thruster can cause a sharp increase in the discharge current; hence, the optimal cathode position should be determined. It was also found that a small inclination angle was favorable for obtaining high performance. In addition, a strong correlation was found between the plume image and thruster performance. Under improved performance conditions, the visible light region of the plume had a shorter axial length and a broader pink halo. Finally, a comparative experiment was conducted on a thruster with an outer magnetic shell. The thruster of this structure was observed to be insensitive to the cathode position; hence, to protect the cathode from ion sputtering, the distance between the cathode and thruster can be appropriately increased.

Analisis Perbandingan Kinerja Brushless Motor Menggunakan Metode Eksperimen

Upaya penghematan energi menjadi tantangan dalam perancangan sebuah teknologi UAV. Salah satu komponen UAV yang banyak tersedia di pasaran adalah brushless motor. Ada kemungkinan kinerja komponen UAV tidak sesuai dengan data spesifikasi yang ada. Oleh karena itu, perlu dilakukan pengujian komponen sebelum merancang sebuah UAV. Makalah ini menyajikan hasil pengujian kinerja brushless motor tipe A2212(6T), MR2205, dan MT2204. Kinerja brushless motor dilihat berdasarkan besarnya daya dorong (thrust), daya yang dikonsumsi (power) dan rasio antara thrust terhadap daya (N/W). Pengujian brushless motor ini menggunakan metode eksperimen. Dalam pengujian ini digunakan propeler empat blade tipe 5140 dan catu daya dengan kapasitas output DC 15-30 V/50 A. Hasil pengujian pada daya rendah menunjukkan bahwa brushless motor tipe A2212(6T)-2200KV membutuhkan daya rata-rata sebesar 25,858 W dengan rasio sebesar 0,042 N/W, tipe MR2205-2300KV membutuhkan daya rata-rata sebesar 22,166 W dengan rasio sebesar 0,052 N/W, dan tipe MT2204-2300KV membutuhkan daya rata-rata sebesar 24,675 W dengan rasio sebesar 0,047 N/W. Berdasarkan data pengujian pada arus kerja di bawah 1,877 A, diketahui bahwa brushless motor tipe MR2205-2300KV memiliki kinerja yang paling baik karena membutuhkan daya paling kecil dan memiliki nilai rasio yang paling tinggi jika dibandingkan dengan kedua tipe lainnya.

Seismic Behavior of Triple Tunnel Complex in Soft Soil Subjected to Transverse Shaking

Combining multiple tunnels into a single tunnel complex while keeping the surrounding area compact is a complicated procedure. The condition becomes more complex when soft soil is present and the area is prone to seismic activity. Seismic vibrations produce sudden ground shaking, which causes a sharp decrease in the shear strength and bearing capacity of the soil. This results in larger ground displacements and deformation of structures located at the surface and within the soil mass. The deformations are more pronounced at shallower depths and near the ground surface. Tunnels located in that area are also affected and can undergo excessive distortions and uplift. The condition becomes worse if the tunnel area is larger, and, thus, the respective tunnel complex needs to be properly evaluated. In this research, a novel triple tunnel complex formed by combining three closely spaced tunnels is numerically analyzed using Plaxis 2D software under variable dynamic loadings. The effect of variations in lining thickness, the inner supporting structure, embedment depth on the produced ground displacements, tunnel deformations, resisting bending moments, and the developed thrusts are studied in detail. The triple tunnel complex is also compared with the rectangular and equivalent horizontal twin tunnel complexes in terms of generated thrusts and resisted seismic-induced bending moments. From the results, it is concluded that increased thickness of the lining, inner structure, and greater embedment depth results in decreased ground displacements, tunnel deformations, and increased resistance to seismic-induced bending moments. The comparison of shapes revealed that the triple tunnel complex has better resistance against moments with the least amount of thrust and surface heave produced.

Experiments of Drilling Titanium Alloy with Varying Operation Parameters

Drilling experiments of titanium alloy Ti6Al4V were conducted. Taking the speed and feed as the process variables, a set of experimental cutting forces are obtained and compared. From the experimental results it is concluded that within the experimental extent the thrust force and torque of drilling process rises with the feed rate. The lower spindle speed resulted in the greater amount of thrust. Feed rates have greater influence on the thrust force than the spindle speed. The combination of greater feed rate and lower spindle speed results in the maximum amount of thrust. However, combination of greater feed rate and spindle speed resulted in maximum amount of torque.

Propellant-Less Thrust Generation - A Review

This paper introduces a concept of propellant-less microwave thruster for upper stage and space applications. The propellant-less microwave thruster works on classical electromagnetic theory, where the microwave radiations are converted to the electromagnetic pressure that acts as axial thrust. In microwave thrusters, microwaves are radiated to a sealed conical cavity which follows the contour of the thrusters to produce pressure. Normally, there are three types of methods by which thrust can be produced without utilizing any propellant. Cannae Drive, EmDrive, and the Wrap Drive are mostly used. The first two are based on the principle of microwave radiation, whereas the third method is just a concept in various science fiction films. The EmDrive can produce a small amount of thrust, therefore, its application is limited to upper stage thruster, orbit/trajectory correction, and deep-space exploration. This paper provides an insight on the feasibility of EmDrive for space application by comparing its performance with ion propulsion system. The proposed microwave propulsion system has low system mass (typically in Kgs), produces high thrust (in mN) and even has higher specific impulse (in years) which can outweigh the current ion propulsion system.

Review on Typical Ingredients for Ammonium Perchlorate Based Solid Propellant

Ammonium perchlorate (AP) based solid propellant is a modern solid rocket propellant used in various applications. The combustion characteristics of AP based composite propellants were extensively studied by many research scholars to gain higher thrust. The amount of thrust and the thrust profile, which may be obtained from a specific grain design, is mainly determined by the propellant composition and the manufacturing process that produces the solid propellant. This article is intended to review and discuss several aspects of the composition and preparation of the solid rocket propellant. The analysis covers the main ingredients of AP based propellants such as the binder, oxidizer, metal fuel, and plasticizers. The main conclusions are derived from each of its components with specific methods of good manufacturing practices. In conclusion, the AP based solid propellant, like other composite propellants is highly influenced by its composition. However, the quality of the finished grain is mainly due to the manufacturing process.

Designing Space Cold Gas Propulsion System using Three Methods: Genetic Algorithms, Simulated Annealing and Particle Swarm

Cold gas propulsion system technology is relatively less expensive than other propulsion systems. In this paper, for five usual gas as propellant and eight genera as structural used in this systems, first Isp (specific impulse) was checked and then, using three optimization methods, i.e. genetic algorithms, simulated annealing and particle swarm, the optimal total mass of system, principles of structure design, optimal chamber pressure and radius propellant tank were calculated as a multidisciplinary for each gas and structure. Using the results, it is possible to determine the gas, the suitable structure and configuration of the design; for this example, the results of the three algorithms were compared. Assuming that the amount of Thrust, working time and the size of thruster cylindrical chamber is given, it is evident that the gas which have the most Isp is not necessarily a good criterion to be used in the design stage of the cold gas system, and other criteria such as the total mass of the propulsion system, chamber pressure, the radius of the tank and the size of the structures must also be considered.

Computational Fluid Dynamics Simulation of Tip-to-Tail for Hypersonic Test Vehicle

Computational fluid dynamics simulations are carried out for a complete hypersonic vehicle integrating both external (nonreacting) and internal (reacting) flow together to calculate the scramjet combustor performance and vehicle net thrust minus drag. Simulations are carried out for a flight Mach number of about six. Three-dimensional Navier–Stokes equations are solved along with the shear stress transport turbulence model and single-step chemical reaction based on fast chemistry. The Lagrangian particle tracking method for droplets is used for combustion of kerosene fuel. Flow is largely nonuniform at the inlet of the combustor. Mass flow of ingested air increases with increase in angle of attack. Because of more combustion of fuel, wall surface pressure is higher for compared with . Combustion efficiency and thrust achieved are found to increase with the increase in angle of attack. Considerable amount of thrust is obtained from a single expansion ram nozzle and achievement of positive thrust–drag for the whole vehicle is demonstrated. The computational analysis of the whole vehicle provides net forces and moments of the whole vehicle, which is very useful for the mission analysis of the vehicle.

Wear Prognostic on Turbofan Engines

One of the most evident characteristic of wear for a turbofan engine is the exhaust gas temperature (EGT). It seems clear that this temperature increases when some carbon deposits on the turbine, when the compressor efficiency diminishes so the fuel flow should increase to produce the same amount of thrust, or even when some unbalance opens the spaces between the turbine and the casing. In any cases, an increase of the EGT should be analyzed because it is a wear symptom of the engine. It is mostly concluded by a water wash in the best case or a shop visit inspection and repair in the worst case. The engine manufacturer defines a schedule plan with its customer based on consumption of the EGT margin. This margin is the amount of available increase of the exhaust temperature before an inspection. Contractually, the engine is restored with a minimum EGT margin after each repair. Thus it is up to the manufacturer to understand how this margin is used to plan shop visits and to the company to estimate the current state of its engine. However, the EGT measurement is subject to a lot of noise and the company regularly washes their engines to increase randomly the margin and their capabilities. In this article we present a simple, automatic and embeddable algorithmic method to transform the successive EGT measurements in a delay indicator computed after each flight giving the amount of available use time. One challenge is to take care of the random wash or repair executed by the user. Finally this indicator may be transmitted automatically with the other data broadcasted by the aircraft computer (ACMS/ACARS) and it is used by the manufacturer to prepare his shop logistic.

Design Algorithm for Upper Stage’s Attitude Control System

Inserting a satellite into different orbit of injection orbit require an orbital maneuver. In addition, the orbit maneuver needs a suitable control of upper stage. Providing required angles is the duty of this control and it must be able to come over disturbances. This paper, with looking over Attitude Control Systems (ACS) used in upper stages, introduces an algorithm for design and sizing of upper stage`s ACS considering requirements and constraints. The algorithm derives required ACS propellant mass, tanks value, feeding pressure, amount of thrust, combustion chamber pressure and total mass of ACS. Presented algorithm needs minimum inputs and estimates the outputs using accuracy experimental functions and scientific theorems. Finally the algorithm is validated by some real cases.

A quantitative assessment of varus thrust in patients with medial knee osteoarthritis

Varus thrust is an abnormal lateral knee motion frequently seen in patients with medial knee osteoarthritis (OA) during gait. It is a worsening of the alignment in the stance phase of the gait cycle and closely relates to disease progression. In this study, we measured the thrust quantitatively using skin markers and examined the relationship to other static and dynamic parameters. Forty-four knees in 32 patients (mean age, 72years; range, 64–81years) who exhibited the radiographic OA at least grade 2 according to the Kellgren–Lawrence (K–L) scale were enrolled. Gait analysis was performed for each patient to measure the amount of thrust and knee adduction moment. The amounts of thrust in subjects with K–L grades 2 (25 knees), 3 (13 knees), and 4 (6 knees) were 2.4°(±1.3°), 2.8°(±1.4°), and 7.2°(±5.3°), respectively and the knee adduction moments were 3.6(±1.5) %BW⁎Ht, 3.9(±1.2) %BW⁎Ht and 6.9(±2.2%) BW⁎Ht, respectively. The amount of thrust also exhibited significant correlation to static radiographic alignment (R=0.47: 95% confidence interval 0.67–0.21, p=0.0038) and showed greater correlation to the knee adduction moment (R=0.73: 95% confidence interval 0.84–0.55, p<0.001), which has been identified as an important dynamic index of the disease. The amount of thrust, which is able to be measured by simple inexpensive equipment, correlated to static and dynamic parameters and may offer an important clinical index for knee OA.

Propulsion characteristics of wing-in-ground effect dual-foil propulsors

Propulsion characteristics of wing-in-ground effect propulsors were investigated using a comparative analysis of thrust and powering characteristics between wing-in-ground (WIG) effect thrusters and traditional screw propellers. WIG thrusters were found to have constant thrust production and efficiency, nearly independent of speed of advance, as contrary to screw propellers, whose optimum efficiency occurs at only one speed point. To produce the same amount of thrust as equivalent screw propellers, WIG thrusters have to work under heavily loaded operating conditions. WIG thrusters were also found to produce a relatively lower but nearly constant efficiency and thrust, independent of speed. Another distinguishing propulsion characteristic revealed for WIG thrusters is that they are capable of operating at much higher speeds, in a range of three to six times that of screw propellers of the same size. While the speed range of screw propellers is mainly limited by their geometric pitch, the speed range of WIG thrusters has no speed limit in ideal fluid. In reality, the speed range is only limited by viscous drag and cavitation, or compressibility, in water or air, respectively. This suggests a potential for WIG thrusters of higher speed application than screw propellers. An experimental investigation and validation of the propulsion system is warranted.

Foreland Deformation--A Critique of Cause: ABSTRACT

The cause of foreland deformation has been argued for nearly 100 years, and despite definitive stratigraphy, superb exposure, and extensive seismic and well data, mechanism and geometry remain elusive. It is necessary to separate arguments for cause from arguments that only support a particular geometric interpretation. The following statements are presented for discussion and are not advanced as the answer. (1) Foreland deformation is caused by end-load buckling in a plate tectonic setting driven by abnormally shallow subduction. (2) The crust is active (competent) unit, and plastic subcrust is a passive cushion allowing great vertical component, though a slight slope forced on it by subducting slab may have aided telescoping of crust above. (3) No strictly vertical cause can allow basins to go down as much as they did, and active (causal) intrusion under uplifts only is not likely. (4) While reverse faults and modest shortening predominate, fault attitudes can End_Page 1353------------------------------ have greater diversity than in thin-skinned regime because plastic substratum allows easy vertical motion; nearly vertical faults are allowable. (5) The basement does fold, but with difficulty and in broad wavelength. (6) Because of broad arching, a exists well within basement over uplifts, allowing high-level features, such as Rattlesnake Mountain, to be bounded by high-angle normal faults. (7) This same neutral surface forces out-of-the-basin crowding, causing steep flanks of most basin folds to face toward adjacent uplift. (8) The Hafner approach illustrates diversity of curved faults that can be generated in a vertically sinusoidally loaded beam, and which can be generated equally well in an end-loaded sinusoidally buckled beam, as long as it sits on a passive plastic substratum. (9) The Sanford model is excellent for depicting fault configuration generated in sediments above a high-angle fault. (10) Faults such as Dinosaur Monument can be seen to steepen downward, but my models suggest that they go listric at their lower transition with plastic substratum. (11) The COCORP trace of Wind River fault indicating a nearly planar 35° dipping fault most of way through crust is probably real; arguments that you cannot see a fault of granite against granite do not apply. (12) Gravity highs over uplifts, models, and later collapsed uplifts speak for a flexed and slab configuration and against a buoyant root configuration. (13) Thrusting from several different directions appears not to be a when viewed in context of jostled slabs. (14) Blocky corners do place limits on amount of thrust and strike-slip translation. (15) The argument for pure verticality to solve a presume space problem in Piney Creek structure loses validity as soon as bounding tears are allowed to stray from a perfectly vertical dip. (16) The argument at Elk Mountain that dip of bounding structure must be at least as low-angle as degree of overturning of sedimentary panels is wrong (proven by Five Springs). (17) Sales' eastward crowding of Colorado Plateau and development of a Wyoming couple north of it still seems cogent. (18) The Chapin and Cather, and Gries subdivision into movement phase also appears to be correct. (19) If horizontal compression is a reality, Stone must be correct in principle; there have to be logical connecting structures. (20) The crust can transmit stress over great distances because it is weak enough; southeast Asia tectonics require greater distances of stress transmittal than Laramide foreland tectonics. End_of_Article - Last_Page 1354------------

The Opunake, New Zealand, earthquake of 5 November 1974

Abtract The Opunake earthquake (ML = 6.1) was centred at 39°.54S, 173°.45E, very near the Maui gas field, at a shallow depth. This is about 35 km off the SW Taranaki coast in a region where the Cape Egmont fault zone forms the western margin of the Taranaki graben. Damage due to the event was minor. The focal mechanism solution implies an equal amount of thrust and strike-slip motion, and a nearly horizontal compression-axis that trends NE-SW. The aftershock sequence (128 events with ML ⩾ 3.5 up to the end of November) was of long duration and had a high b-value of 1.35. The aftershock epicentres occupied an area of about 15 X 10 km. The main event is somewhat unusual in that it was, for its magnitude, a very compact event (radius of equivalent circular dislocation 6 km) with a large displacement (0.17 m) and high stressdrop (1.2 X 106 N/m2) .

Engines for Supersonic Civil Transport Aircraft

Because of its high overall pressure ratio and good propulsive efficiency, the jet engine is very efficient for supersonic propulsion. A high thrust per unit power plant frontal area and per unit weight are primary requirements and these imply high combustion temperatures. For a Mach 2.0 aircraft, engine design problems other than this are not outside existing experience but additional problems, such as bearing cooling, become more serious at cruise Mach Numbers approaching 3.0. A variable intake is essential and the method of geometry variation and control requirements are described. Variable propulsion nozzle design is also an area of vital importance and it is not claimed that an entirely satisfactory solution, giving good performance with low drag in the transonic phase, has yet been achieved. The ‘sonic boom’ phenomenon can have an important influence on engine design, in that it may determine the maximum altitude at which the aircraft has to fly subsonically. Should this be appreciably above the tropopause, then it will not only influence the amount of thrust installed but may also dictate the fitment of reheat for the transonic acceleration. Take‐off noise is a requirement which can influence both the installed thrust and the choice of engine type. Despite the lack of firm standards for field noise and ‘coast‐over’ noise, there is good reason to believe that the noise levels of a supersonic transport need not exceed those of the quieter long‐range subsonic transports in service at this time.

A Comparison of Ion and Plasma Propulsion

Several important features and parameters of ion and plasma accelerators for propulsion are compared. Estimates for the thrust of individual ion and plasma acceleration units are given. Impulse measurements for a collinear electrode plasma accelerator are presented. The maximum thrust for an ion gun does not depend on the diameter of the beam, but primarily on the accelerating voltage. Because of the relatively small thrust of the ion accelerator, a greater number of them will be required for a given total amount of thrust. Estimates indicate that the ion accelerator may be somewhat more efficient; however, further experiments are needed to determine the efficiency of both types of accelerators. Beam neutralization is a problem peculiar to the ion accelerator. Considerable research and development may be necessary to provide a satisfactory method for neutralizing the ions. An estimate of the power for neutralization is made. The variation of efficiency with specific impulse is discussed. Further experiments are needed to determine the most efficient ranges of specific impulse for both types of accelerators. Erosion is a serious problem in electrical propulsion; however, for a plasma accelerator it may actually be utilized to provide the propellant material.