Propeller Thrust Research Articles

Methodical and algorithmic aspects of mathematical modeling of a screw aircraft power plant

The article describes the solution of a scientific problem that consists in expanding the functionality of the program “Calculation of the traction-economic and mass-specific characteristics of the power plant and aircraft motion parameters” through the introduction of additional algorithms and mathematical models for calculating the altitude-speed characteristics of screw aircraft power installations. At the same time, an internal calculation of the aircraft propeller thrust is used according to experimental aerodynamic coefficients, which makes it possible to increase the efficiency and reliability of complex theoretical studies of power plants of various types as part of aircraft at the stage of external design. A description is given of the developed algorithms: an algorithm for converting power on the output shaft of a gas turbine engine into thrust of an aircraft power plant; a mathematical model of a propeller that provides calculation of its thrust from experimental aerodynamic coefficients; an algorithm for determining the thrust of the power plant, taking into account the compressibility of the air and the interaction of the propeller and the elements of the airframe of the aircraft. Some features of the mathematical modeling of an aircraft propeller are revealed, in particular, the principle of propeller control by influencing the blade angle and rotational speed depending on the aircraft flight speed and a method for constructing the field of aerodynamic characteristics of an aircraft propeller in a wide range of blade angle and speed coefficient. In conclusion, the results of verification of the modified program are presented with an analysis of the obtained altitude-speed characteristics.

A Simplified Model for Propeller Thrust in Oblique Flow

New aircraft architectures are being proposed for unmanned aerial vehicles and air taxis, which include tilt-able motor and propellers. These propulsive units operate with a propeller axis at an angle oblique to the flight direction, and thus it is important to understand and model how thrust is produced by a propeller operating under these conditions. Propellers in oblique flow have been modeled using Blade Element Momentum Theory coupled to an inflow model, and the Vortex Lattice Method. In the present work, we develop a much simpler approach that neglects the crossflow component of the incoming air velocity. An advance ratio is developed based on the parallel inflow component, and is coupled to existing propeller data collected in axial flow conditions. The proposed model is evaluated using existing experimental data collected under oblique flow conditions, and is predicts thrust to within \(5\,\%\) of experimental values for most conditions. The greatest discrepancy between the model and experiments occurs in the pure crossflow case, which is of lesser importance in the application to unmanned aerial vehicles and air taxis.

Research on numerical prediction of hydrodynamic interference under coupling of pod propeller and hull

Abstract Taking the cable-laying ship and the pod propeller as the research objects, based on the Reynolds time-averaged RANS equation and sliding moving grid technology, the self-propulsion numerical calculation of the coupling of the pod propeller and the hull was completed. By comparing the resistance of the bare hull and the thrust of the pod propeller, the hydrodynamic interference under the coupling state of the pod propeller and the hull is analyzed. The results show that when Fr=0.295, the total resistance of the ship increases by 21.6%, the pressure difference resistance increases by 30.5%, the wake fraction is 0.011, and the thrust derating is 0.178. The research results provide theoretical and technical guidance on the interference problem between the hull and the pod propeller.

Design selection of experimental test rig for static thrust on micro size propeller using Pugh method

This paper aims to propose a simple, straightforward, yet robust test rig design to measure the static thrust magnitude for small propellers. Although there were advanced tools like multi-axis force or torque sensors, sophisticated equipment and complex mechanisms were required to capture the accurate thrust magnitude. Therefore, providing simple and effective test rig design for small-sized propellers is quite challenging. In this work, Pugh matrix analysis was used to evaluate three new designs of Propeller Thrust Measurement Rig (PMTR) and compare the designs against a benchmark model. The evaluation covered important design criteria during test operation, such as measurement accuracy, stability, ease of development, assembly, maintenance, versatility, electronic integration, airflow interference, adaptability for tilt angle studies, and resemblance to multicopter flight conditions. The results reveal that the PMTR-1 design scored the highest in the analysis and emerged as the most suitable candidate among the proposed designs. It showed potential superior performance in stability, ease of development and assembly, versatility, simplicity, airflow management, and adaptability for future studies. PMTR-3 demonstrated some potential but needs more enhancement in electronic integration and structural development. However, PMTR-2 faces significant potential challenges in providing stability, versatility, electronic integration, and adaptability for effective and safe operations.

Design of a Human Muscle-Powered Flying Machine

This study explores the design and development of a human-powered aircraft (HPA), leveraging modern engineering techniques, materials science, and advanced CAD/CAM tools. The project addresses key aspects of aircraft design, including the geometry of wings and tail, control and power transmission mechanisms, propeller selection, and material identification to achieve ultra-lightweight construction. The 3DExperience platform facilitated comprehensive model creation, simulation, and production process development, while XFLR5 was employed for aerodynamic profile analysis using the vortex lattice and panel methods. JavaProp aided in evaluating propeller thrust and power requirements. Computational fluid dynamics (CFD) simulations using the SST k-ω turbulence model provided critical insights into flow behavior. The design was found to be theoretically capable of flight, although challenges arose in selecting appropriate software for aerodynamic analysis, leading to the use of XFLR5 for early-stage design and the more advanced 3DExperience platform for final evaluations. Although structural strength analyses were not performed due to the complexity of composite materials, future work in this area could enhance the precision of component selection and aircraft mass estimation.

Fluid-Solid Coupling Analysis of the Propeller and Optimization of Boss Cap Fin Parameters

In order to ensure the accuracy of propeller modelling and hydrodynamic performance prediction, first of all, compared with atlas modelling and OpenProp modelling, it is pointed out that the characteristics of the blade model established by PropCad are more complete. Secondly, through the analysis and discussion of the computational domain distribution, grid independence verification and turbulence model, the CFD calculation model is established systematically. Thirdly, the hydrodynamic analysis of AU5-80 propeller is carried out under different advance ratios, and the simulation results are in good agreement with the open water test data. The accuracy of CFD calculation model is proved. Then, the fluid-solid coupling analysis of the propeller is performed, and it is verified that the stress field of the propeller meets the material strength requirement. It provides support for the further optimization design of propeller structure. Finally, through the design and analysis of the PBCF propeller, some optimization parameters of the PBCF are obtained. Because the PBCF can diffuse and weaken the hub vortex, the propeller thrust, and efficiency are improved.

An efficient method to simulate ship self-propulsion in shallow waters and its application to optimize hull lines

Emerging environmental challenges, such as pronounced low water levels and a constantly increasing transport volume, underscore the need to address logistical complexities and to refocus attention on the performance of self-propulsion vessels in restricted and confined waters. Recognizing the demand for an accurate and efficient ship design method, we modified an actuator disk model to predict ship propulsion. This model was designed to be applicable to various kinds of ships, with special features tailored to meet the specific requirements of inland water vessels, particularly those equipped with ducted propellers. We implemented this model into the open-source CFD software library OpenFOAM to be used in conjunction with either single- or multiphase incompressible solvers. We validated this implemented model against model test data, thereby demonstrating its capability to accurately predict propulsion performance of a typical inland waterway vessel. Following validation, we employed this model in an automated optimization process, demonstrating its robust and efficient applicability for a practical user-defined case to improve a ship's afterbody lines. Meticulous grid convergence studies ensured the predictive convergence of our simulations. Our validation covered various ship speeds at three distinct water depths, ranging from a moderate water depth-to-draft ratio h/T of 2.67 to an extreme shallow water depth-to-draft ratio h/T of 1.25. We validated our simulated results against data extracted from our own previous model tests, comprising measured ship trim and ship sinkage, propeller thrust, duct thrust, propeller torque, propeller revolution rate, and propulsion power. We investigated the influence of water depth also on various parameters, such as friction and pressure distributions, free surface interactions, and velocity patterns. Finally, we integrated the developed method into an automated optimization process that we tailored for a selected test cases of the considered ship operating in water depth to draft ratios h/T of 2.67. This integrated process facilitated the systematic refinement of the ship's afterbody lines, representing a crucial step in the pursuit to enhance ship performance.

Simultaneous identification of propeller fluctuating forces and unknown parameters based on a Bayesian inversion approach

Accurate quantification of propeller excitation is essential for effective vibro-acoustic analysis and mitigation in marine vessels. This study introduces a Bayesian statistical framework that indirectly reconstruct uncertain forces and system parameters by fusing available prior information, forward modeling and measured vibration responses through Bayesian theorem. The Markov Chain Monte Carlo (MCMC) algorithm, enhanced with Polynomial Chaos Kriging (PC-Kriging) surrogates, is employed to facilitate efficient estimation of likelihood functions and robust uncertainty propagation, providing posterior probabilistic estimates and credible intervals for the identified forces. Additionally, the framework incorporates model class selection based on model evidence to determine the most plausible empirical spectrum model for the propeller broadband thrust spectrum. Specifically, this study proposes and evaluates two candidate empirical spectrum models, the Ornstein–Uhlenbeck (OU)-Gaussian and OU-Weibull models, which effectively capture the frequency–amplitude characteristics of unsteady thrust. Numerical results demonstrate substantial parameter uncertainty reduction, accurate thrust spectrum reconstruction, and effective quantification of statistical properties. Moreover, the OU-Gaussian model is revealed to be more plausible for characterizing the propeller thrust spectrum and response prediction. This framework may offer a practical solution for propeller excitation identification, enabling rapid vibro-acoustic performance assessments of marine vessels.

Numerical investigation on the ventilated supercavitating model with propeller

To achieve stable and continuous supercavitating flow over underwater vehicles, artificial ventilation is implemented, particularly effective at lower speeds. Previous research on supercavitation primarily focused on analyzing ventilated supercavitating flow with various cavitator types and/or ventilation rates. In this investigation, we examine the behavior of ventilated supercavitating flow over an axisymmetric model featuring both a disk cavitator and a Postdam propeller placed at the bow. Utilizing the Large Eddy Simulation turbulence model, Volume of Fluid method, and Kunz cavitation model, our simulation aims to capture the cavitating flow around the propeller and the ventilated supercavitating flow over the model. Validation of our numerical methods is achieved by comparing our results with experimental data of a ventilated model by Chung and Cho [“Ventilated supercavitation around a moving body in a still fluid: Observation and drag measurement,” J. Fluid Mech. 854, 367–419 (2018)] and the cavitating Postdam propeller by SVA Postdam [S. Potsdam, “PPTC smp'11 Workshop,” in Proceedings of the Workshop on Cavitation and Propeller Performance (2011)]. The results show that with a rotating propeller at the bow of the supercavitating model, the cavitating flow extends and stabilizes compared to configurations utilizing a traditional disk cavitator. The presence of the propeller accelerates the formation of supercavitating flow at a consistent incoming flow speed. Additionally, coupling the propeller with the disk cavitator results in significant increases in propeller thrust, torque, and efficiency. While there is an observed rise in model drag, the impact is not substantial.

Wind-tunnel experimental investigation on rotor-rotor aerodynamic interaction in compound helicopter configuration

In recent years, the compound helicopter configuration, featuring the addition of lateral propellers to a helicopter main rotor, has gained renewed interest for its ability to achieve higher flight speed. The aerodynamic behaviour of compound rotorcraft is dominated by mutual interactions between the rotors and the wakes they generate, which can affect their performance and the handling qualities of the aircraft. In order to study the effects of the rotor-wake and wake-wake interactions, a test rig was developed and an extensive wind-tunnel test campaign was carried out measuring the performance of rotor and propellers under different flight conditions. Hovering flight and forward flight at different advance ratios were considered, as well as crosswind flight under various wind directions. In general, an increase in thrust for both main rotor and propellers is found due to the interaction. In particular, the significant increase in the propeller thrust is attributed to the influence of the main rotor downwash, which impacts edgewise on the propellers. In some specific conditions, a decrease in the propeller's thrust is observed, which might be related to blade-vortex interaction (BVI) effects. To aid in the interpretation of the experimental results, numerical simulations with a mid-fidelity aerodynamic code were also performed.

Effects of adverse sea conditions on the dynamic performance of a cruise ship integrated power system

In adverse sea conditions, changes in the propeller emergence depth can cause propulsion load fluctuations, resulting in significant variations in ship-integrated power systems (IPS). These fluctuations can severely affect the power quality of ships and the operational efficiency of electrical devices. To develop appropriate mitigation measures against the impact of wind and waves on IPS, a comprehensive model that can simulate the response characteristics of the hull and IPS for different heading angles in different sea conditions is necessary. This paper presents an integrated multi-system dynamic model capable of simulating the response characteristics of a ship's hull and its IPS under the wind and waves interference. A novel method is proposed to estimate propeller thrust and torque loss directly from the ship's pitch and roll angles. Utilizing this dynamic model, the responses characteristics of the hull and IPS in varying sea conditions have been investigated. The findings demonstrate that the model accurately captures variations in ship motions, as well as IPS voltage and frequency, under wind and waves interference. Additionally, this study explores the application of a hybrid energy storage system (HESS) to enhance the IPS power quality in the context of Sea State (SS) 7. Results indicate that the HESS has good potential to compensate for propulsion load fluctuations, thereby mitigating the negative impacts on the ship's IPS.

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.

Experimental analysis of propeller thrust in an undergraduate physics laboratory

As propulsive systems are challenging for undergraduates to understand, it is essential to design experiments that can help their visualization and testing. The development of digital technology (high-speed cameras, digital tracking software, or 3D printers) facilitates the implementation of such designs. We proposed to study the thrust produced by a propeller, whose operating principles are based on the conservation of linear momentum. The study was carried out on an air track to avoid frictional forces. Several system characteristics were established, such as the propellor’s rotation speed and angle of attack and different magnitudes were determined, including the dynamic thrust and static force values. 3D CAD software was used to design the propellers for the experiments, and 3D printers to produce them.

Design and research of an electric unmanned aerial vehicle power system

An Electric power test system of UAVs is presented, which can be applied to validate the efficiency of UAV propulsion systems and provide reliable verification for propeller numerical calculations. The design proposal, working principle, test equipment and test experiment is introducted. Reliability of various functions of the system is examined and assessed through the multiple comparisond tests, which indicates that, when subjected to identical conditions, the numerical solutions for propeller thrust, torque, and motor efficiency exhibit average errors of 1.02%, 10%, and 10.04%, respectively. The results indicate that the power system test platform effectively validates numerical calculation results, providing reliable engineering application value for general UAV propulsion system research. The findings of this study offer support for optimizing power systems of the UAV, providing valuable references for future engineering applications and development.

Propeller Ceiling Effect in Forward Flight

The study extends the investigation of the fixed-pitch small-scale propeller in the ceiling effect to forward flight conditions at different propeller incidence angles. Force-based experiments, phase-locked particle image velocimetry (PIV), and surface oil flow visualization were conducted on two APC propellers at the University of Dayton Low Speed Wind Tunnel. For propellers in edgewise flight, the power required at constant thrust decreases at small advance ratios for each h/D and then increases with a further increase in the advance ratio. Tilting the propeller forward reduces the ceiling effect benefits in both thrust and power, particularly at higher advance ratios. Performance similarity in the propeller ceiling effect at different h/D is observed, and a performance prediction method is proposed. Phase-locked PIV showed an increase in the propeller inflow angle in the ceiling effect at small advance ratios, resulting in higher thrust generation. This effect reduces with an increase in the advance ratio due to minimized interactions with the ceiling plate. Hence, the measured propeller in-ceiling-effect (ICE) propeller performance cannot represent the propeller ICE performance at a higher forward flight speed. Additionally, PIV and surface flow visualization indicated the presence of a stagnation point on the ceiling plate near the trailing side of the propeller disk at higher advance ratios, leading to a reduction in propeller thrust generation.

Rapid dynamic aeroelastic response analysis of the highly flexible wing with distributed propellers influence

Abstract A rapid nonlinear aeroelastic framework for the analysis of the highly flexible wing with distributed propellers is presented, validated and applied to investigate the propeller effects on the wing dynamic response and aeroelastic stability. In the framework, nonlinear beam elements based on the co-rotational method are applied for the large-deformation wing structure, and an efficient cylinder coordinate generation method is proposed for attached propellers at different position. By taking advantage of the relatively slow dynamics of the high-aspect-ratio wing, propeller wake is modeled as a quasi-steady skewed vortex cylinder with no updating process to reduce the high computational cost. Axial and tangential induced velocities are derived and included in the unsteady vortex lattice method. For the numerical cases explored, results indicate that large deformation causes thrust to produce wing negative torsion which limits the displacement oscillation, and slipstream mainly increases the response values. In addition, an improvement of flutter boundary is found with the increase of propeller thrust while slipstream brings a destabilising effect as a result of the increment of dynamic pressure and local lift. The great potential of distributed propellers in gust alleviation and flutter suppression of such aircraft is pointed out and the method as well as conclusions in this paper can provide further guidance.

System Identification and Dynamic Analysis of the Propulsion Shaft Systems Using Response Surface Optimization Technique

Marine vessels rely heavily on propeller shaft systems to adjust the engine torque and propeller thrust. However, these systems are subjected to various dynamic excitations during operation, such as transverse, longitudinal, and torsional excitations. These excitations can arise from factors like non-uniform stern flow fields, misaligned components, and the whirling motion of the shafts, which can affect the integrity and reliability of the vehicle. To analyze the dynamic response of the propulsion shaft system and ensure its reliability, numerical/analytical models are currently in practice. The finite element method (FEM) is a popular choice, but uncertainties in bearings and connectors stiffness lead to inaccuracies in the Finite Element model, resulting in significant differences between the experimental and theoretical models. This paper proposes the response surface optimization (RSO) technique to estimate unknown bearing stiffness in the propulsion shaft system. The experimental model of the propeller shaft system is constructed using steady-state response with step sine excitation. The RSO technique is then used to update the natural frequencies and vibration amplitude of the FE (Finite Element) model. The updated model shows less than a 10% difference in natural frequencies and vibration amplitude compared to the experimental model, demonstrating that the proposed technique is an efficient tool for marine shaft dynamic analysis.

Electric Motor Chain Modeling Using Artificial Neural Networks and Semi-Empirical Methods

The methodology presented in this paper is dedicated to a user who wants to design a power chain of an electric unmanned aerial vehicle. The power chain includes a brushless direct current (BLDC) motor, a propeller, and a battery. Three models are presented to predict the thrust, electrical consumption, mechanical torque, and rotational speed provided by each component of an electrical power chain. Only public data were used to design these models. The research was developed in order to be used by all people who want to buy electrical power chain components and therefore to model their properties. Neural networks set with MATLAB parameters were used to design BLDC motor output (rotational speed and mechanical torque) models. Empirical methods such as blade element theory (BET) and disk area were used to model propeller thrust. A battery discharge model was designed based on public datasheets. Very good prediction results were obtained for the rotational speed (0.20% of error) and torque (0.45% of error). Small thrust modeling errors of 1.06% were found with the BET method. Models presented in this research could be designed using a wide type of data, such as public data (provided on manufacturer websites) or real test bench measurements.

Hydrodynamic Performance Analysis of Camber Ratio Variations on B-series Propeller Types

The hydrodynamic performance of the B-series propeller can be determined by calculating the polynomial equation published by MARIN. Furthermore, analysis and evaluation of B-series propeller modifications can be done by varying the camber ratio of the foil. The camber ratio affects the lift force on the propeller foil, directly affecting the propeller thrust and torque. Numerical calculations were carried out using Computational Fluids Dynamics (CFD), based on Reynolds Averaged Navier Stokes Equations (RANSE) and turbulence model in the form of explicit algebraic stress models (EASM). The overall results of this study show an increase in efficiency of 4.182 on the foil with a camber ratio of 2.2% when compared to the foil camber ratio of 0%.

Research on the hydrodynamic performance of propellers under oblique flow conditions

The phenomenon of oblique water inflow is widespread in the operation of thrusters, which will cause adverse effects on the hydrodynamic performance of thrusters. In order to investigate the hydrodynamic performance and stress variation of the propeller in oblique flow, based on computational fluid dynamics theory, this paper takes the DTMB4119 propeller as the research object and conducts numerical simulation research on the propeller in oblique flow by solving the RANS equation. By calculating the open water performance curve and surface pressure distribution of the propeller, the rationality of the numerical method and the meshing are verified. Considering the flow field information such as velocity, oblique flow angles, flow line distribution, and pressure distribution, the changes in hydrodynamic characteristics of the propeller are simulated and analyzed. The results show that the uneven distribution of pressure on the propeller blade surface increases with a decrease in the advance coefficient. The force pulsation amplitude of a single blade increases with an increase in oblique flow angles. With the increase in oblique flow angles, the thrust, torque, and efficiency of the propeller show different increasing trends. With the increase in propeller advance coefficient, propeller thrust and torque decrease gradually, and propeller efficiency increases gradually. By using mature propellers, this paper has more reference value for studying the flow field around the ship hull and the hydrodynamic performance of propellers in the process of ship maneuvering.