Static Thrust Research Articles

Performance analysis of bio-inspired transformable robotic fish tail

We simulate, validate and analyze the performance of a transformable tail of an adaptive robotic fish based on the propulsion of three bio-inspired body deformations similar to those of the big-eye trevally, the butterfish, and the boxfish. The objective is to enable robotic fish operation in rapidly changing underwater environments that may require transitions between swimming modes. The bio-inspired propulsion tail consists of a passive caudal fin attached to three articulated segments each actuated by a servomotor to produce desired deformations. Representing these deformations by analytical functions, the linkage lengths of the three segments are optimized using Simscape. A testing platform, equipped with a load cell and a distance laser sensor, is developed to measure and validate the predicted thrust and forward speed over a range of undulation frequencies and amplitudes of lateral oscillations. Static thrust values are also compared to their theoretical counterparts obtained from Lighthill's theory of elongated bodies' propulsion. The results show that the locomotion modes alone can impact the swimming performance over an unchanging morphology. The experimental results further indicate that synchronicity of locomotion parameters found in nature has a greater effect on the overall thrust than varying a specific parameter.

Variable‐geometry exit nozzle for improving static thrust of drones ducted fans

AbstractUnmanned aerial vehicles, or drones, are a technology that has seen rapid growth. Their ability to offload tasks that are once considered labor intensive is one of their many appealing aspects. This aspect increases time for tasks of higher importance, meaning reliance on this technology is ever increasing. These tasks include land geo‐mapping, firefighting, surveillance, delivery services, search and rescue among others. As with every growing technology, however, comes the negative exposure, shadowing further expansion and growth. For drones, this includes noise pollution, and hazardous, low efficiency propulsion systems. Regulations and laws are beginning to surface, regulating the use of drones and their noise levels within airspace, as future growth can overcrowd airspace. Current drones use propulsion systems that expose the public to hazardous propellers and high levels of noise, thus unsuitable for their expected growth. This paper presents a novel variable‐geometry exit nozzle to improve the efficiency of current propulsion systems in drones, in turn reducing noise levels and hazards, that are currently foreshadowing drones. The presented propulsion method achieves results that show better performance than a ducted fan and propeller under static conditions. Three experiments are conducted, and the results are reported and discussed.

An investigation of euro diesel-hydrogen dual-fuel combustion at different speeds in a small turbojet engine

PurposeThis study seeks the effect on static thrust, thrust specific energy consumption (TSEC) and exhaust emissions of euro diesel-hydrogen dual-fuel combustion in a small turbojet engine.Design/methodology/approachExperimental studies are performed in a JetCat P80-SE type small turbojet engine. Euro diesel and hydrogen is fed through two different inlets in a common rail distributing fuel to the nozzles. Euro diesel fuel is fed by a liquid fuel pump to the engine, while hydrogen is fed by a fuel-line with a pressure of 5 bars from a gas cylinder with a pressure of approximately 200 bars.FindingsAt different engine speeds, it is found that there is a decrease at the TSEC between a range of 1% and 4.8% by different hydrogen energy fractions (HEF).Research limitations/implicationsThe amount of hydrogen is adjusted corresponding to a range of 0–20% of the total heat energy of the euro diesel and hydrogen fuels. The small turbojet engine is operated between a range of 35,000 and 95,000 rpm engine speeds.Practical implicationsOn the other hand, remarkable improvements in exhaust emissions (i.e. CO, CO2, HC and NOx) are observed with HEFs.Originality/valueThis is through providing improvements in performance and exhaust emissions using hydrogen as an alternative to conventional jet fuel in gas turbine engines.

Secondary Eddy Current Losses Reduction in a Double-Sided Long-Primary Fractional Slot Concentrated Winding Permanent Magnet Linear Synchronous Motor

A novel design method for the primary structure of a double-sided long-primary fractional-slot concentrated winding permanent magnet linear synchronous motor (DSLP-FSCW-PMLSM) is proposed in this article. Different from the traditional symmetric primary structure, the primary structure obtained by the proposed design method has two asymmetric primary cores and two asymmetric primary windings. This unique structure can reduce the variation of the flux density caused by the primary core slotting, and can effectively reduce the slot harmonic contents of the armature reaction magnetic field; thus, it can significantly reduce secondary eddy current losses. First, the basic structure is introduced. The air-gap magnetic field of permanent magnet and armature reaction are analyzed in detail. Second, the performance of the proposed motor is analyzed by means of three dimensional finite element method and compared with the traditional motor. The focus is on secondary materials, secondary eddy current losses, thrust, pole arc coefficient, magnet skew angle, and efficiency. Last, experiments are conducted on two prototypes of DSLP-FSCW-PMLSM. The validity of the proposed topology is verified by the test results of static thrust, back electromotive force, and armature reaction air-gap magnetic field.

Design and Analysis of a High Thrust Linear Voice Coil Motor Using for the Stiffness Test of Linear Motor Servo System

Linear voice coil motors (VCMs) are widely used in some high precision or high dynamic applications, such as lithography, digital cameras, and microscopes. In this article, a high thrust linear VCM is analyzed and designed, which is used for the position loop stiffness test of linear motor servo system. To guarantee the structural strength of coil frame and provide space for the cooling channels, the two layers’ coil arrangement is adopted. Based on 2-D finite element method (FEM), the thrust and thrust ripple performance of the motor are analyzed. Moreover, a reasonable cooling structure integrated with the coil frame is designed to further improve the thrust density. Finally, a linear VCM prototype with a thrust rating of 1000 N is manufactured and tested. The static thrust test results show that the thrust varies linearly with the coil current. The motor can provide a nearly constant thrust and thrust ripple within ±2 mm displacement is less than 1%, which agrees well with finite element simulation. In addition, the temperature test is also achieved. Compared with natural cooling condition, the thermal equilibrium can be achieved among the coil, coil frame and cooling water with the water-cooling condition, when the current density is 15.3 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Furthermore, a good overall cooling effect and low surface temperature rise can be realized when two heat shield cover plates are fixed onto both sides of the primary.

The control of quadcopter propeller radiated noise

Simple scaling analysis is used to show that significant reductions in quadcopter propeller radiated noise can be achieved, at the hover condition, by reducing the quadcopter and/or payload weight to, in turn, reduce the propeller tip speed. The scaling analysis shows that the propeller radiated noise, at the hover condition, scales as the cube of the combined quadcopter and payload weight. The reductions in radiated noise predicted from the scaling analysis are verified experimentally with quadcopter propellers in an anechoic chamber. Experiments also show that reducing the propeller tip speed by increasing the propeller blade pitch or blade number, while maintaining a given static thrust, is ineffective at reducing the radiated noise. In fact, it is shown that too high a blade pitch and/or blade number can significantly increase propeller radiated noise even though the blade tip speed is significantly reduced. This is attributed to increased propeller blade and blade wake interactions for the increased blade pitch and number.

Improvement of the slotless tubular permanent magnet linear motor with lighter mover mass for punching applications

The slotless tubular permanent magnet linear motor (STPMLM) offers obvious advantages when it is applied to the punching system, such as space saving and controllable impact strength. Herein, the mechanical and electromagnetic coupled differential equations were established to present a comprehensive analysis of the relationship between mover mass and motor performance in the punching system. The travel time of the punching movement was expressed analytically under the condition of the mover obtaining the same impact kinetic energy, and the relationship between the mover mass and the resistive energy consumption in one punching process was also deduced under the same condition. Then the analytical results were validated by a numerical model. The studies show that a lighter mover mass can contribute to less resistive energy consumption and faster dynamic response in the punching applications. Based on that, a STPMLM with special-shaped yoke was designed for lighter mover mass. Moreover, prototype experiments including static thrust characteristic and dynamic performance were conducted. The experimental results proved that the proposed permanent magnet linear motor with special-shaped yoke can improve the dynamic performance and reduce resistive energy consumption while ensuring that the electromagnetic performance is not affected.

Improvement of Electric Propulsion System Model for Performance Analysis of Large-Size Multicopter UAVs

In this study, an improved model of the electric propulsion system is proposed in order to analyze the performance of large-size multicopter unmanned aerial vehicles. The main improvement of the proposed model is to reflect the armature reaction of the motor, which effectively explains the significant performance degradation in high-power operation. The armature reaction is a phenomenon, in which the main field flux is interfered by a magnetic flux and, as the size and output of the motor increase, the effect of armature reaction also rapidly increases. Therefore, the armature reaction must be considered for the optimal design and performance analysis of large-size multicopter platforms. The model proposed in this study includes several mathematical models for propellers, motors, electric speed controllers, and batteries, which are key components of the electric propulsion system, and they can calculate key performance data, such as thrust and torque and power consumption, according to given product specifications and input conditions. However, estimates of the armature reaction constants and heat profiles of motors need to be obtained in advance through experimental methods, since there is not yet enough data available in order to derive an estimation model. In conclusion, a comparison with the static thrust test of some commercial products confirmed that the proposed model could predict performance in the high-power operation of electric propulsion systems for large multicopter platforms, although some errors were noted.

Influence of high oxygenated biofuels on micro-gas turbine engine for reduced emission

Purpose This paper aims to investigate the effect of additives in Jet-A fuel blends, especially on performance, combustion and emission characteristics. Design/methodology/approach Jet-A fuel was formed by using Kay’s and Gruenberg–Nissan mixing rules by adding additive glycerol with TiO2. While measuring the combustion performance, the amount of oxygen content present in fuel and atomization are the key factors to consider. As such, the Jet-A fuel was created by adding additives at different proportion. A small gas turbine engine was used for conducting tests. All tests were carried out at different load conditions for all the fuel blends such as neat Jet-A fuel, G10T (glycerol 10% with 50 ppm TiO2 and Jet-A 90%), G20T (glycerol 10% with 50 ppm TiO2 and Jet-A 90%) and G30T (glycerol 10% with 50 ppm TiO2 and Jet-A 90%). Findings From tests, the G20T and G10T produced better results than other blends. The thermal efficiency of the blends of G20T and G10T are 22% and 14% higher than neat Jet-A fuel. Further, the improved static thrust with less fuel consumption was noticed in G20T fuel blend. Originality/value The G20T blends showed better performance because of the increased oxygenated compounds in the fuel blends. Moreover, the emission rate of environmentally harmful gases such as NOx, CO and HC was lower than the neat Jet-A fuel. From the results, it is clear that the rate of exergy destruction is more in the combustion chamber than the other components of fuel.

Lowest emission sustainable aviation biofuels as the potential replacement for the Jet-A fuels

Purpose The purpose of this study is to predict the performance and emission characteristics of micro gas turbine engines powered by alternate fuels. The micro gas turbine engine performance, combustion and emission characteristics are analyzed for the jet fuel with different additives. Design/methodology/approach The experimental investigation was carried out with Jet A-1 fuel on the gas turbine engines at different load conditions. The primary blends of the Jet A-1 fuels are from canola and solid waste pyrolysis oil. Then the ultrasonication of highly concentrated multiwall carbon nanotubes is carried with the primary blends of canola (Jet-A fuel 70%, canola 20% and 10% ethanol) and P20E (Jet-A 70% fuel, 20% PO and 10% ethanol). Findings The consumption of the fuel is appreciable with the blends at a very high static thrust. The 39% reduction in thrust specific fuel consumption associated with a 32% enhance in static thrust with P20E blend among different fuel blends. Moreover, due to the increase in ethanol concentration in the blends PO20E and C20E lead to a 22% rise in thermal efficiency and a 9% increase in higher oxygen content is observed. Practical implications The gas turbine engine emits very low emission of gases such as CO, CO2 and NOx by using the fuel blends, which typically reduces the fossil fuel usage limits with reduced pollutants. Originality/value The emission of the gas turbine engines is further optimized with the addition of hydrogen in Jet-A fuel. That is leading to high specific fuel exergy and owing to the lower carbon content in the hydrogen fuel when compared with that of the fossil fuels used in gas turbine engines. Therefore, the usage of hydrogen with nanofluids was so promising based on the results obtained for replacing fossil fuels.

Experimental investigation of performance and emission characteristics of a miniature gas turbine supplied by blends of kerosene and waste tyre pyrolysis oil

Fossil fuels are non-renewable sources of energy that could be depleted in the near future, giving rise to a major energy crisis. Scientists from all over the world are working on new technologies to produce fuel not only from renewable sources but also from waste. This article is concerned with: (i) waste tyre management by means of the pyrolysis process, (ii) investigation of physico-chemical parameters of waste tyre pyrolysis oil (TPO), and (iii) investigation of performance and emission characteristics of a miniature GTM-140 turbine engine supplied by blends of kerosene and waste tyre pyrolysis oil. The final aim of the research is to determine the influence of the applied blend composition (between 10 and 50% of TPO in the blends) on the performance and emission parameters of a small gas turbine. Turbine inlet and outlet temperatures, fuel flow, static thrust, thrust specific fuel consumption (TSFC) and emissions index of NOx, CO, SO2 are measured in a wide range of turbine load. The differences are the largest for the highest rotational speeds, where the temperatures, TSFC and emissions of NOx especially tend to increase with the increasing fraction of pyrolytic oil in the blends, as compared to those of kerosene. However, emissions of SO2 are lower for the all blends in the entire range of load.

Estimasi Gaya Dorong Dari Motor Brushless Dengan Variasi Propeller Untuk Pesawat Model X-UAV Mini Talon Dengan Menggunakan Pengukur Massa

One that affects aircraft performance is the thrust. The thrust is determined according to the requirements of the aircraft itself. This study uses a thrust test stand that uses a mass gauge as a thrust gauge, using two brushless motors and five propellers to determine the optimal thrust for X-UAV Mini Talon aircraft flying missions. The thrust required by the X-UAV Mini Talon aircraft - is known to be 0.6755 N for cruise flights and 4.979 N for take-off aircraft. After testing, the smallest thrust is produced by the configuration of the DYS 2826-13 brushless motor with a 5x3 inch propeller, while the biggest thrust by the RacerStar BR2212 brushless motor with a 10x6 inch propeller. Compared to calculations with propeller static thrust equation, the difference in thrust in testing with propeller static thrust ranges from 15% to 25%. Therefore, the optimal configuration for flying cruising is the DYS 2826-13 brushless motor with a 5x3 inch propeller, which produces a thrust of 0.988 N. Then, for the optimal configuration take-off is the Brushless DYS 2826-13 with a 9x5 inch propeller, which results in a thrust of 6,151. The configuration above was chosen because it is more efficient, with smaller current requirements compared to other configurations with more or less equivalent thrust.

Virtual Modelling and Testing of the Single and Contra-Rotating Co-Axial Propeller

Propellers are a vital component to achieve successful and reliable operation of drones. However, the drone developer faces many challenges while selecting a propeller and a common approach is to perform static thrust measurement. However, the selection of a propeller using a static thrust measurement system is time-consuming. To overcome a need for the static thrust system a virtual model has been developed for measuring both the static and dynamic thrust of a single and coaxial propeller. The virtual model is reliable enough to minimize the need for full-scale tests. The virtual model has been built using two open-source software Qblade and OpenFoam. Qblade is employed to obtain the lift and drag coefficients of the propeller’s airfoil section. OpenFoam is utilized to perform the flow simulations of propellers and for obtaining the thrust and torque data of the propeller. The developed virtual model is validated with experimental data and the experimental data are obtained by developing a multi-force balance system for measuring thrusts and torques of a single and a pair of coaxial contra-rotating propellers. The data obtained from the propeller virtual model are compared with the measurement data. For a single propeller, the virtual model shows that the estimated forces are close to the experiment at lower rotational speeds. For coaxial propellers, there are some deviations at the rear propeller due to the turbulence and flow disturbance caused by the front propeller. However, the computed thrust data are still accurate enough to be used in selecting the propeller. The studies indicate that in the future, these virtual models will minimize a need for experimental testing.

Measuring Wind Speed Using the Internal Stabilization System of a Quadrotor Drone

This article proposes a method of measuring wind speed using the data logged by the autopilot of a quadrotor drone. Theoretical equations from works on quadrotor control are utilized and supplemented to form the theoretical framework. Static thrust tests provide the necessary parameters for calculating wind estimates. Flight tests were conducted at a test site with laminar wind conditions with the quadrotor hovering next to a static 2D ultrasonic anemometer with wind speeds between 0–5 m/s. Horizontal wind estimates achieve exceptionally good results with root mean square error (RMSE) values between 0.26–0.29 m/s for wind speed, as well as between 4.1–4.9 for wind direction. The flexibility of this new method simplifies the process, decreases the cost, and adds new application areas for wind measurements.

Impact of additives in Jet-A fuel blends on combustion, emission and exergetic analysis using a micro-gas turbine engine

This study focuses on combustion, emission, and performance analysis of JET-A fuel blends with various additives using a micro gas turbine engine. The amount of oxygen in fuel blends and atomization are the crucial parameters in the production of a higher combustion rate with less emission. Therefore, various ratios of additives (ethanol and pentanol) are blended with biofuel (rapeseed and canola-sunflower oil) to form the JET-A fuel blends by using Kay’s and Grunberg-Nissan mixing rules. The combustion, performance and emission parameters under different engine loads were examined. Results showed that all the blends logged higher static thrust with an appreciable reduction rate in the consumption of the fuel. Among different fuel blends, R20E (Jet-A 70% fuel, 20% Rapeseed, and 10% ethanol) showed 35% increase in static thrust associated with 41% reduction in thrust specific fuel consumption. Moreover, the blends R20E and CS20E (Jet-A fuel 70%, Canola- Sunflower 20% and 10% ethanol) indicated 24% and 10% increase in thermal efficiency respectively due to the influence of ethanol concentration and higher oxygen content. In addition, these fuel blends generate less emission of environmental unfriendly harmful gases, including NOx, CO, and HC, compared to neat Jet-A fuel. Results revealed that the exergy destruction values are higher for the combustion chamber than the other conventional fuel components.

Linear Vernier actuator with two movers

Background: Linear motion devices for industrial machines and robots are expected to realize their high efficiency drive and simple structure. Usually, a feed screw mechanism composed of a rotary motor and a ball-screw or slide-screw is employed. However, it has some problems such as the decrease of the drive efficiency, flexibility against external forces, noise, etc. Various linear actuators and motors have been developed utilizing the feature of a direct drive.&#x0D; Aim: In this paper, we propose a novel linear actuator which 2 movers can be independently controlled using 3-phase and 6-phase superimposed currents for decreasing the size and weight of the system. The proposed linear actuator is driven by the operating principle of a vernier motor which is expected to achieve a high thrust force density per permanent magnet volume.&#x0D; Methods: The operating principle and the static thrust force characteristics of the proposed linear actuator are verified by an electromagnetic field analysis using 3-D finite element method, and the back electromotive force characteristics are also analyzed. In addition, the dynamic characteristics under position feedback control are analyzed. The control system uses a vector control using PID controller, and the control input is given by the 3-phase and 6-phase superimposed currents.&#x0D; Results: The static force characteristics were investigated. From the analyzed results, the force interference between the two movers was small. Moreover, the interference of the back electromotive force of the 3-phase and 6-phase movers were not observed. The movers could be independently driven under position feedback control using 3-phase and 6-phase superimposed currents. The dynamic characteristics analyses showed that the mover well followed a target position. From a step response, the time constant and the response of the position feedback system were investigated.&#x0D; Conclusion: This paper presents a linear vernier actuator with two movers. The basic structure and operating principle of the actuator were described. Moreover, the static characteristics and the dynamic characteristics under position feedback control were analyzed. It was found that the movers can be independently driven.

Modelling & numerical exploration of pulsejet engine using eddy dissipation combustion model

The pulsejet engine is relatively simple engine used in missiles but the combustion modeling of pulsejet engine is relatively complex through numerical analysis procedure. The current research investigates the application of eddy dissipation model in analyzing the combustion and thus thrust generation. Three different fuel inlet designs of pulsejet engine are considered for analysis i.e. single inlet, three inlet and five inlets. The Jet Air combustion is modeled under pseudo static steady state conditions. The CFD analysis is conducted using ANSYS CFX analysis package and CAD model is developed in PTC Creo design software. The static enthalpy, thrust and velocity are determined for all the three designs. The research findings have shown that the fuel to air ratio has significant effect on thrust generation from pulsejet engine. The turbulence kinetic energy is highest near the walls and near nozzle which reduces as we move away from it.

The Effect of TiO2 on Engine Emissions for Gas Turbine engine Fueled with jatropha, butanol, Soya and Rapeseed Oil

AbstractThis paper aims in assessing the effect of biofuel blend such as butanol, jatropha methyl ester, soya methyl ester and rapeseed methyl ester as an additive for the aviation fuel. In addition to the blends, the nanoparticle TiO2 of 3 % is added to the biofuel. The nanoparticle mixed at the concentration of 300ppm by ultrasonication process. The fuel Jet A, B27T, J27T, S27T and R27T are investigated for combustion and emission characteristics for various throttle settings in micro gas turbine engine. Addition of additives improves the ultimate property of the fuel by reducing the kinematic viscosity. The fuel blend B27T reports 25 % increase in total static thrust and 22 % reduction in thrust specific fuel consumption. From the results it is evident that, all fuel blends showed a significant reduction in emission values owing to high oxygen content. In addition, the thermal efficiency of the B27T and J27T is improved appreciably to 30 % and 10 % higher than Jet A fuel owing to the influence of the nanoparticle TiO2. On the other hand, the emissions like CO and NOx reduced drastically up to 70 % and 45 % respectively.

Design and Dynamic Performance Study on Hydrostatic Lubrication System of High-speed Precision Roller Grinding Head

To meet the need of high-speed steel roll grinding, a hydrostatic lubrication system for high-speed precision roller grinding head is designed and the dynamic performance of the system is simulated and analyzed in this study. The hydrostatic lubrication system was designed according to the lubrication characteristics of the eccentric sleeve and thrust bearing of the high-speed precision roller. Then the mathematical models of the main components of the system were established. And according to the schematic diagram of hydrostatic lubrication system, the dynamic performance of the lubrication system at high speed was simulated and tested. The simulation and experiment results show that the lubrication effect of the eccentric sleeve static chambers and thrust bearings is good, and the designed hydrostatic lubrication system is feasible.

Новый способ увеличения тяги воздушного винта путем применения дополнительной несущей поверхности

Air propellers used in small scale unmanned aircraft operate at low Reynolds numbers. The aerody-namic force occurring on the blade when the air propeller is in operation is of variable nature. It is observed that for Reynold numbers below 5⋅105 flow separation can occur on some sections of the propeller surface. To deal with the problem, increase the lift on the blade and therefore, reduce the turbulence boundary level, a new design called bi-blade propeller is developed and patented. This design features an additional blade above the main one. Using ANSYS Fluent, samples of the bi-blade propellers were investigated to determine the positions where the inductive resistence and the turbulence boundary level decreased, and the lift increased when the air propeller was in operation. A comparison study was conducted in laboratory conditions to investigate static thrust of the bi-blade propeller on a test bench at 2000–4500 мин–1. The bi-blade propeller was compared with a conventional propeller.