Thrust Parameters Research Articles

Experimental study and performance analysis of a dual-mode space propulsion system pressurized by electric pump

This study presents a new dual-mode propulsion system that utilizes an electrically pumped hydrogen peroxide and kerosene supply system, specifically designed for advanced spacecraft orbit and attitude control. The system incorporates two distinct electric pumps, one for hydrogen peroxide and another for kerosene, each engineered to optimize the propellant feed for the orbit control and attitude control engines. This configuration enables precise propellant management and thrust control, which are critical for the stringent demands of modern space missions. The dual-mode capability of the propulsion system allows for the use of hydrogen peroxide both as a monopropellant in the attitude control engine and as an oxidizer in combination with kerosene in the orbit control engine. This approach simplifies the propulsion architecture while maximizing the efficiency and utility of hydrogen peroxide as a propellant. The electric pumps are essential in providing high-pressure propellant delivery, which is necessary to achieve the desired combustion characteristics and thrust parameters. Performance evaluations of the propulsion system demonstrated significant results. The orbit control engine achieved a combustion chamber pressure of 5.9 MPa and a combustion efficiency of 98.42 %. The attitude control engine, operating at a peak pressure of 4.9 MPa, exhibited a stable pulsative mode, maintaining consistent pressure levels throughout its operational cycle. These performance metrics highlight the effectiveness of the electric pump technology in enhancing propulsion system responsiveness and efficiency. This propulsion system is expected to improve spacecraft maneuverability and reduce operational costs, making it suitable for long-duration space missions.

Novel NSTEX System Based on Ti/CuO/NC Nanothermite Doped with NTO

Modern energetic materials (EMs), e.g., nanothermite and NSTEX (Nanostructured Thermites and Explosive) compositions are attracting increasing research interest. In this work, we present the results of our investigation on the properties of a novel Ti/CuO nanothermite system doped with cellulose nitrate (NC) and 5-Nitro-1,2-dihydro-3H-1,2,4-triazin-3-one (NTO). In terms of safety parameters, the friction (40–>360 N), impact (40–>50 J) and laser irradiation sensitivity were determined for tested systems, which indicated tunable properties. The combustion velocity (up to 735 m/s), pressure parameters for combustion in closed vessel, thrust parameters and open-air combustion behaviour were measured. Moreover, in order to deeply study the impact of NTO on the combustion mechanism, SEM, DSC/TG and XRD analyses were conducted. The obtained results indicate that the Ti/CuO/NC/NTO system is extremely promising for future applications.

Jumping Motor Skills in Typically Developing Preschool Children Assessed Using a Battery of Tests.

The preschool period is characterised by the improvement in motor skills. One of the developmental tasks in children is the ability to jump. Jumping plays an important role in the development of leg strength and balance. It is the gateway to more complex movements. In the physiotherapy clinic, we see a lot of difficulties in jumping performance in 5-7-year-old children. The aim of this study is to present the jumping ability, assessed by the Motor Proficiency Test (MOT) and the G-sensor examination of the vertical countermovement jump (CMJ) and countermovement jump with arms thrust (CMJAT) parameters. A total of 47 children (14 boys and 33 girls) were randomly recruited. The mean age was 5.5 years. The mean height was 113 cm and the mean weight was 19.7 kg. The children were divided into two groups according to their results. Children with low basic motor skills have the greatest difficulty with jumping tasks. In the CMJ jump, the take-off force was lower than in the CMJAT (p = 0.04). Most CMJAT parameters correlate with age, weight, and height. Height correlates most with children's jumping performance. This study may be useful for sport educators and developmental researchers. The topic should be further explored and the CMJ and CMJAT parameters may be established as a basis.

Rotation-traction manipulation induced intradiskal pressure changes in cervical spine-an in vitro study.

Objective: Evaluate the effect of rotation-traction manipulation on intradiskal pressure in human cervical spine specimen with different force and duration parameters, and compare the intradiskal pressure changes between rotation-traction manipulation and traction. Methods: Seven human cervical spine specimens were included in this study. The intradiskal pressure was measured by miniature pressure sensor implanting in the nucleus pulposus. rotation-traction manipulation and cervical spine traction were simulated using the MTS biomechanical machine. Varied thrust forces (50N, 150N, and 250N) and durations (0.05s, 0.1s, and 0.15s) were applied during rotation-traction manipulation with Intradiscal pressure recorded in the neutral position, rotation-anteflexion position, preloading, and thrusting phases. Futuremore, we documented changes in intradiscal pressure during cervical spine traction with different loading forces (50N, 150N, and 250N). And a comparative analysis was performed to discern the impact on intradiscal pressure between manipulation and traction. Results: Manipulation application induced a significant reduction in intradiscal pressure during preloading and thrusting phases for each cervical intervertebral disc (p < 0.05). When adjusting thrust parameters, a discernible decrease in intradiscal pressure was observed with increasing thrust force, and the variations between different thrust forces were statistically significant (p < 0.05). Conversely, changes in duration did not yield a significant impact on intradiscal pressure (p > 0.05). Additionally, after traction with varying loading forces (50N, 150N, 250N), a noteworthy decrease in intradiscal pressure was observed (p < 0.05). And a comparative analysis revealed that rotation-traction manipulation more markedly reduced intradiscal pressure compared to traction alone (p < 0.05). Conclusion: Both rotation-traction manipulation and cervical spine traction can reduce intradiscal pressure, exhibiting a positive correlation with force. Notably, manipulation elicits more pronounced and immediate decompression effect, contributing a potential biomechanical rationale for its therapeutic efficacy.

Modified modeling and internal model control method of thrust ripples in PMLSMs for ultraprecision air-bearing linear feed systems

With the aim of attenuating thrust ripples in ultraprecision air-bearing linear feed systems, a simple and effective internal model control (IMC) system is herein presented based on a modified modeling and identification method of permanent magnet linear synchronous motors (PMLSMs). First, flux linkage equations were used to describe the volt–ampere characteristics of PMLSMs and provide a thrust expression in a differential form based on the principle of virtual work. Then, an analytical formula was obtained through derivation based on the condition of field-oriented control. On this basis, an IMC compensator was designed using an inverse model to attenuate nonlinear thrust effects, and an extended Kalman filter (EKF) was adopted to estimate the actual current in an analog linear amplifier. The boundedness of the nonlinear system was analyzed based on the convergence condition; furthermore, the stability of the proposed IMC compensator with EKF could be guaranteed. Then, an accurate model and thrust parameters were obtained using an identification experiment on an air-bearing linear platform driven by a linear analog amplifier. To demonstrate the coupling effect of current on thrust and confirm the effectiveness of the proposed method, both simulations and experiments were performed at a uniform velocity under extra loads of different weights; then, an extended state observer (ESO) was introduced as a comparative method. Finally, the results of the following error indicated that the proposed method demonstrated improved performance in terms of overcoming the influence of nonlinearity and that it results in smooth velocities in steady states.

Thrust Integrated Trajectory Optimization for Multipulse Rocket Missiles Using Convex Programming

In this paper, a thrust integrated trajectory optimization algorithm for multipulse rocket missiles is proposed. Maximizing terminal velocity is selected as a performance index for achieving high maneuverability in the homing stage. To incorporate the optimization of thrust profile, thrust parameters are also considered as optimization variables with several thrust constraints such as impulse conservation and maximum/minimum thrust level. The original trajectory optimization problem is reformulated using new independent variables and timescale variables. This method simplifies the dynamics and makes the impulse conservation constraint disappear. Then, a control-affine system is established by defining the angle of attack and its square as new control inputs. The admissible input set is relaxed to a convex set, and mathematical proof is provided to show that the relaxation preserves the solution. The problem is discretized by applying a pseudospectral method for each subinterval. The solution is then obtained using sequential convex programming (SCP). A quadratic variable trust-region constraint is used for robust convergence of SCP. The proposed method robustly optimizes the thrust parameters and trajectory of the multipulse rocket missile within 1 s. Numerical simulation shows the feasibility and effectiveness of the proposed method.

Многоуровневая математическая модель течения газа в сопловом канале с центральным телом

Supersonic non-isobaric jet outflow was studied under conditions of interaction with the slipstream. Multilevel mathematical model was compiled making it possible to analyze structure of the gas-dynamic flow in the vicinity of the nozzle channel central body at the aircraft take-off path (0...10 km). Multilevel approach to calculating thrust parameters of the nozzle channel with central body requires development of a physical and mathematical model of the non-stationary interdependent processes that characterize operation of the “aircraft – nozzle cluster – jet” system as a whole. At the same time, it is necessary to form mathematical models of the processes for different degrees of the task detailing, i.e. within each scale of the task (micro-, meso- and macro-scale). Mathematical model includes calculation of the aircraft traction characteristics, study of the interaction features between the jet, the central body and the slipstream.

Methods and Algorithms of Turbojet Engines Thrust Parameters Control Unerroric

This report shows a real way for solving the problem of turbojet engine thrust parameters control in flight. The purpose of the research is the formalization of the digital methods and its algorithms for turbojet engines thrust parameters control unerroric. The methods of deductive digital signal processing and combined method of system analysis and approximate synthesis are used for such research. It is described the digital algorithms of unerroric methods wich are based on rotor speed control for turbojet engines of twin-engine airliner by its power plant control system. There are given the calculation formulas for those algorithms.

Study on the stability of artificial vibration points with internal resonance in solar sail dynamics

In this paper, the linear and stability of solar sail spacecraft at the libration point of artificial balance is studied. The stability has been analyzed for the linear cases and nonresonance cases. The changing law of artificial balance point is found when the attitude angle of solar sail is fixed. The linear stability region of the solar sail spacecraft at L4 was found. Based on the circular restricted three-body problem, the dynamic model of the continuous solar sail spacecraft is established. The variation law of the position of manual translational point with the β parameters is analyzed. The condition and existence range of linear stability of artificial translational point are given. The influence of thrust parameters on the system and manual translational point is analyzed. The dynamics equation of the solar sail spacecraft near the linearly stable artificial translational point and the nonlinear vibration theory, the range of the system mass parameters and thrust parameters when the system has 1:2 and 1:3 internal resonance is obtained. Using the multi-scale method, the stability of the long and short period motion of the detector is analyzed, and the boundedness of motion is proved.

Influence of cavity configuration parameters on discharge characteristics of capillary discharge based pulsed plasma thruster

Capillary discharge based pulsed plasma thrusters have great prospects of applications in in-orbit maneuvering of&lt;bold/&gt; micro-nano satellites. In this paper, the influence of different capillary cavity structure parameters on the thruster's energy deposition process, ablation characteristics, output thrust parameters and plasma plume parameters under an energy level of 5 J were studied. The experimental results indicate that the increase of the inner diameter of the capillary cavity will significantly reduce the discharge current density, which leads the deposition energy and equivalent power to decrease; the increase of the cavity length helps to improve the energy transfer efficiency. The influence of cavity structure on the ablation characteristics is reflected in the influence of deposition energy per unit area on the tube wall temperature. When the inner diameter of the capillary increases from 1 mm to 3 mm, the ablation mass decreases significantly, and then the equivalent ablation mass remains approximately unchanged as the inner diameter of the cavity increases further; the ablation mass continues to increase as the capillary length increases, while the ablation mass per unit area continues to decrease. The impulse bit depends on the ablation mass and plasma plume velocity, and the difference in ablation characteristic further affects the plasma in the cavity. The density and equivalent pressure determine the plasma electrothermal acceleration process. The continuous increase in the diameter and length of the capillary cavity will induce the acceleration process to lag behind the discharge and ablation process. And the decrease of the deposited energy impedes the electrothermal acceleration process, which results in the decrease of the impulse bit, specific impulse, and the overall efficiency. Furthermore, the overall efficiency transfer model analysis indicates the influence of the capillary inner diameter on thruster efficiency is mainly reflected in the energy transfer efficiency, and the capillary length change mainly affects the electrothermal acceleration efficiency. The overall efficiency optimization of the thruster needs to start from increasing both energy deposition efficiency and acceleration efficiency.

Анализ эффективности использования электрореактивных двигателей для поддержания низкой орбиты малого космического аппарата

This paper examines the problem of maintaining the plane parameters of the working orbit of a small spacecraft using an electric propulsion engine. In low working orbits, due to the Earth’s atmosphere, a spacecraft is subjected to aerodynamic drag forces, which results in a decrease in the radius of the orbit and a potential termination of the useful target functioning. The time parameters of the cyclogram for maintaining the working orbit of a small spacecraft with an electric low thrust engine are analyzed taking into account the variability of the atmospheric density. The cyclogram consists of sections of the passive and active movement under the action of the low thrust engine. For the satellite under study, suitable thrust parameters of the electric engine are selected, which allow the correction of the plane parameters of the low orbit. Using the characteristics of the thrust and specific impulse of the electric jet engine, fuel reserves for correction over a long period of time are calculated. The results of the analysis confirm the effectiveness of the electric propulsion engine in terms of fuel consumption for correction.

Sliding Mode Control for Micro Turbojet Engine Using Turbofan Power Ratio as Control Law

The interest in turbojet engines was emerging in the past years due to their simplicity. The purpose of this article is to investigate sliding mode control (SMC) for a micro turbojet engine based on an unconventional compound thermodynamic parameter called Turbofan Power Ratio (TPR) and prove its advantage over traditional linear methods and thrust parameters. Based on previous research by the authors, TPR can be applied to single stream turbojet engines as it varies proportionally to thrust, thus it is suitable as control law. The turbojet is modeled by a linear, parameter-varying structure, and variable structure sliding mode control has been selected to control the system, as it offers excellent disturbance rejection and provides robustness against discrepancies between mathematical model and real plant as well. Both model and control system have been created in MATLAB® Simulink®, data from real measurement have been taken to evaluate control system performance. The same assessment is conducted with conventional Proportional-Integral-Derivative (PID) controllers and showed the superiority of SMC, furthermore TPR computation using turbine discharge temperature was proven. Based on the results of the simulation, a controller layout is proposed and its feasibility is investigated. The utilization of TPR results in more accurate thrust output, meanwhile it allows better insight into the thermodynamic process of the engine, hence it carries an additional diagnostic possibility.

A neural network model for UAV propulsion system

PurposeDetermining the performance parameters of the propulsion systems of the aircraft, which is the key product of the aviation industry, plays a critical role in reducing adverse environmental impacts. Therefore, the purpose of this paper is to present a temperature performance template for turbojet engines at the design stage using a neural network model that defines the relationship between the performance parameters obtained from ground tests of a turbojet engine used in unmanned aerial vehicles (UAV).Design/methodology/approachThe main parameters of the flow passing through the engine of the UAV propulsion system, where ground tests were performed, were obtained through the data acquisition system and injected into a neural network model created. Fifteen sensors were mounted on the engine – six temperature sensors, six pressure sensors, two flow meters and one load cell were connected to the data acquisition system to make sense of this physical environment. Subsequently, the artificial neural network (ANN) model as a complement to the approach was used. Thus, the predicted model relationship with the experimental data was created.FindingsFuel flow and thrust parameters were estimated using these components as inputs in the feed-forward neural network. In the network experiments to estimate fuel flow parameter, r-square and mean absolute error were calculated as 0.994 and 0.02, respectively. Similarly, for thrust parameter, these metrics were calculated as 0.994 and 1.42, respectively. In addition, the correlation between fuel flow, thrust parameters and each input parameters was examined. According to this, air compressor inlet (ACinlet,temp) and outlet (ACoutlet,temp) temperatures and combustion chamber (CCinlet,temp, CCoutlet,temp) temperature parameters were determined to affect the output the most. The proposed ANN model is applicable to any turbojet engines to model its behavior.Practical implicationsToday, deep neural networks are the driving force of artificial intelligence studies. In this study, the behavior of a UAV is modeled with neural networks. Neural networks are used here as a regressor. A neural network model has been developed that predicts fuel flow and thrust parameters using the real parameters of a UAV turbojet engine. As a result, satisfactory findings were obtained. In this regard, fuel flow and thrust values of any turbojet engine can be estimated using the neural network hyperparameters proposed in this study. Python codes of the study can be accessed from https://github.com/tekinonlayn/turbojet.Originality/valueThe originality of the study is that it reports the relationships between turbojet engine performance parameters obtained from ground tests using the neural network application with open source Python code. Thus, small-scale unmanned aerial propulsion system provides designers with a template showing the relationship between engine performance parameters.

Контроль параметров тяги двухвальных турбореактивных двигателей при их разнотяговости

Контроль параметров тяги двухвальных турбореактивных двигателей при их разнотяговости

Accurate and Rapid Broadcast Ephemerides for Beidou-Maneuvered Satellites

The geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites of the Beidou navigation satellite system are maneuvered frequently. The broadcast ephemeris can be interrupted for several hours after the maneuver. The orbit-only signal-in-space ranging errors (SISREs) of broadcast ephemerides available after the interruption are over two times larger than the errors during normal periods. To shorten the interruption period and improve the ephemeris accuracy, we propose a two-step orbit recovery strategy based on a piecewise linear thrust model. The turning points of the thrust model are firstly determined by comparison of the kinematic orbit with an integrated orbit free from maneuver; afterward, precise orbit determination (POD) is conducted for the maneuvered satellite by estimating satellite orbital and thrust parameters simultaneously. The observations from the IGS Multi-Global Navigation Satellite System (GNSS) Experiment (MGEX) network and ultra-rapid products of the German Research Center for Geosciences (GFZ) are used for orbit determination of maneuvered satellites from Sep to Nov 2017. The results show that for the rapidly recovered ephemerides, the average orbit-only SISREs are 1.15 and 1.0 m 1 h after maneuvering for GEO and IGSO respectively, which is comparable to the accuracy of Beidou broadcast ephemerides in normal cases.

Centralized Control System Design for Underwater Transportation using two Hovering Autonomous Underwater Vehicles (HAUVs)

Abstract In this paper, a centralized control system is designed for the two HAUVs undertaking underwater transportation of a spherical payload via cylindrical manipulators. First, the nonlinear coupled dynamic model is developed considering the rigid body connection method for transportation. The effect of the hydrodynamic, hydrostatic and thrust parameters are taken about the centre of the combined body i.e. the centre of payload. Path trajectory is generated using the minimum snap trajectory algorithm. The trajectory is divided into segments for each directional motion which is further divided into the waypoints based on the time step of the duration. The path between two waypoints is represented by a 7th order polynomial. The centralized control system is designed to follow the desired trajectory. The control system is designed using PID controllers for the motion control in each direction. The main technical requirements are the stability of the payload, accurate trajectory tracking and robustness to overcome uncertainties. Stability cannot be compromised because of the rigid connection between the vehicles and the payload, whereas, tracking is given a tolerance of ±5%. Transportation task is observed for the desired motion in the horizontal plane. The time domain motion simulation results show that the desired trajectory has been accurately followed by the combined system while meeting the technical requirements.

Investigation of a Low-power Thruster on Krypton Propellant

Nowadays, higher requirements are set for modern spacecraft,and, in particular, those related to the cost-efficiency of the mission. To ensure a reasonably long period of active life (approximately 10-15 years), stationary plasma thrusters (SPT) are successfully used in propulsion systems. Xenon is the substantial part of the cost of the propulsion system, which is why this could be significantly reduced, were xenon to be replaced with an alternative propellant.On this basis, and taking into account the perspectives for the creation of multi- satellite orbital constellations and the tendency towards spacecraft miniaturizations, there is a demand for the development of a low-power thruster using an alternative propellant to Xenon. It is assumed that krypton is the most suitable replacement, albeit while using krypton there is a considerable decrease in the SPT thrust parameters. Therefore, it is necessary to perform investigations which reduce the negative consequences related to the use of krypton as a propellant.

A Multisegmented Long-Stroke Dual-Stator Pulsed Linear Induction Motor for Electromagnetic Catapult

Multisegmented dual-stator pulsed linear induction motor (LIM) is suitable for electromagnetic (EM) catapult based on the former research. This paper mainly analyzes the numerical model of same and reverse mode of the dual stator, magnetic thrust and EM parameters, and the magnetic field distribution has been built by finite-element model and the static performance are gotten by the prototype machine. Based on the analysis results and static experiments, the closed-loop control models for the dual stator have been established, and the dynamic launch test has been performed by using of multisegment prototype LIMs. The test results show that the dual-stator LIMs can accelerate the 300-kg load to the speed of 15 m/s within 11-m launch stroke. The fluctuation of the slip frequency is quite small and the block transition is smooth during the launching process. The test results show good agreement with the commanded values, which verify the dual-stator LIM model and control strategy.

Examination of performance indicators' effects based on propulsion parameters in a turboprop engine

In this study, propulsion indicators and their effects have been described by reference to the actual data of a turboprop engine. Then, the effects of these indicators on exergetic and environmental performance efficiencies have been investigated considering thermal effects of these indicators. Accordingly, sustainable propulsion index parameters have been developed. Primarily the thrust and impacts of fuel-induced effects on the performance have been evaluated separately. Fuel consumption of a turboprop engine is ranging from 2.97 kg/s to 0.85 kg/s between take-off (160.14 kN) and maximum Mach (31.14 kN) in flight process. The average exergy efficiency was found 17.57%. The exergy efficiency of the turboprop engine highly affected by the exergetic values of the each engine component at various thrust requirements. At the end of the study, the evaluations on sustainable thrust management were made depending on the thrust parameters.

Development of a Rotary Drilling Mechanism for Impregnated Diamond Bits

Impregnated diamond core bits are often used in core drilling for geological surveys. A tri-state theory is proposed to describe the three states in drilling processes for a diamond particle or a bit. These states are contacting state, cutting state, and ploughing state. Furthermore, the relations among thrust and other mechanical parameters are also summarized. The optimal value of the specific energy is in the cutting state. Several experiment results verified the proposed model. This mechanism is useful for selecting operation parameters in core drilling using impregnated diamond core bits.