Main Propulsion Research Articles

A guide to unmanned aerial vehicles performance analysis—the MQ‐9 unmanned air vehicle case study

AbstractGreat efforts are devoted for integrating Renewable Energy Sources (RES) on the propulsion system of Unmanned Air Vehicles (UAVs). This is applicable to small UAVs, having a horizon to expand to large UAVs within the next decades. For the conventional propulsion systems to be replaced, the required power needs of the aircraft should first be examined. The required power depends on the UAV's flight stage from takeoff to landing, whereas its calculation varies with regard to the propulsion system type, which is separated into two main categories, the propelled‐driven engines and the jet engines. Two obstacles are arising. First, the parameters needed for the power estimation are commercially sensitive and second the analysis alters with respect to the engine's type. This paper focuses on the mathematical analysis of the required power for both the main propulsion systems, presented extensively for each flight phase, proposing, at the same time, a parameter estimation method which is applicable to any UAV type. The main purpose of this paper is to act as a guide for the calculation of any type UAV's required power at any flight stage. To validate the analysis, the MQ‐9 Reaper/Predator B, a High Altitude Long Endurance (HALE) turboprop UAV produced by General Atomics is analysed. Its unknown parameters are estimated and based on a selected flight profile, the required power in terms of horsepower from takeoff to landing is assessed, for two scenarios regarding the aircraft's initial weight. In the first scenario the UAV has the maximum gross takeoff weight, whereas in the second scenario it does not carry any payload. The estimated required shaft power per flight phase for each scenario is then marked into the TPE331‐10 turboprop engine characteristic curves.

Multidisciplinary design and optimization of winged architectures for reusable launch vehicles

Partially reusable launch vehicle design has raised a great interest in order to minimize the costs of space transportation by recovering and refurbishing the first stage. Several configurations such as toss-back architectures are now operational. These concepts require additional rocket propellant in order to carry the boost-back and landing maneuvers, that induce several losses in terms of payload mass performance for the ascent mission. In order to limit these losses, this paper focuses on the design of two types of architectures to carry out the return-to-launch-site mission. The first, named glide-back, uses the main propulsion system of the first stage to perform a boost-back burn and returns to the landing site by a gliding mode using additional lifting surfaces. The second, named, fly-back, performs the return-to-launch-site mission using several air-breathing engines located in the nose of the first stage combined with lifting surfaces. In this paper, the design of a reusability kit, allowing to provide the first stage with both expendable and reusable capabilities, is investigated. This kit is composed of the lifting surfaces, the nose including the air-breathing propulsive system (for fly-back configuration), landing gears and additional avionics. This paper addresses the design of such reusability kits and presents the mission specifications, the design process relying on Multidisciplinary Design Optimization techniques, the vehicle performance and the optimal trajectories. Different analyses (aero-propulsive, optimal control, operational considerations, etc.) are detailed and trade-offs between the studied configurations are assessed.

Calculation of Comparison of Efficiency of Main Driving Machine Sister Ship

The purpose of this study is to calculate the efficiency ratio of the main propulsion engine of the sister ship. Based on the research focus that has been described in the problem formulation, the type of research used is a type of quantitative research using comparative descriptive methods. This study took data on 2 (two) PELNI passenger ships docked at Makassar port, namely KM Bukit Siguntang and KM Lambelu. The process of data collection, data processing and analyzing research data lasted for 4 (four) months from June to September 2022. From the results of data processing contained in the results of research and discussion, it can be concluded that KM Lambelu engine efficiency of 44.145% where specific fuel consumption is 0.1848. KM Bukit Siguntang engine efficiency of 44.07% where specific fuel consumption is 0.1851.

Pemodelan Perawatan dan Perbaikan Berbasis Keandalan Pada Mesin Induk Tipe Bolnes/10 Dnl di Kapal Latih Taruna

Cadet Training ship which was operated by Politeknik Ilmu Pelayaran Semarang have old enough, it was built in 1984 . In that age, some damages in the machinery occur specially the main propulsion engine. Maintenance activity is done in the hope that it can maintain the machinery function under normal condition.The research is started by data taking from the engine log book to get TTF, by observing the failure pattern, the writer can determine the critical system and component to make its blocks diagram function. Then, the model of component failure is analysed with FMECA and the help of weibull++ software, the writer try to find the exact opportunity distribution parameter. Analysing the reliability quantitatively, the writer finds the component reliability value. Premium solver Microsoft excel is used for optimizing the maintenance and repair schedule determination. The result of the research shows that maintenance interval and optimum repair with minimum cost is designed every two years for the docking. The amount of the budget proposed for 2 years is Rp 1.193.489.636,- divided into 2-years budget proposal, that is Rp 477.395.855,- in the first year or Rp 39.782.988,- each month and Rp. 716.093.782,- in the second year or Rp 59.674.482,-each month.

Dynamic and quantitative risk assessment of Cruise ship pod propulsion system failure: An integrated Type-2 Fuzzy-Bayesian approach

Azipod propulsion has revolutionized the future of ship propulsion and maneuvering operations with over 20 years of experience, eventually improving ship safety, reliability, energy efficiency, and overall vessel performance. However, it consists of technically complex machinery systems; its breakdown can result in many potential failures with severe repercussions. In this work, an accident-based dynamic risk assessment study of the Cruise ship pod propulsion system has been carried out. It is based on the real-ship accident of the Norwegian Star, which resulted in the loss of ship propulsion. When historical accident statistics are limited, traditional methods fail to address the uncertainty, dynamic environment, and quantitative risk assessment problems. The goals include avoiding worst-case scenarios by illustrating the progression of dynamic change in risk and establishing the Bayesian network framework for dealing with uncertainty more effectively. Interval type-2 Fuzzy expert system is integrated with the dynamic Bayesian network and bow-tie model for quantitative risk assessment, which laid the groundwork for the subsequent hazard identification and quantitative risk assessment. This accident network summarizes how pod machinery operational failures can cause accidents. The estimated sensitive machinery nodes such as Main motor failure, propulsion system, and power system failure are the leading causes of pod propulsion system failures on board cruise vessels. Risk analysts and decision-makers in the marine and offshore engineering industry can use the suggested model as a decision support tool to considerably reduce and eliminate potential failures, improving the ship's safety and system reliability.

Static aeroelasticity of the propulsion system of ion propulsion unmanned aerial vehicles

“Ionic wind” generators are used as the main propulsion system in ion propulsion unmanned aerial vehicles (UAVs). Owing to the large size and poor stiffness of the electrode array in the propulsion system, the electrode array is prone to deformation under the flight load. In this work, the thrust characteristics and static aeroelastic properties of “ionic wind” propulsion systems were analyzed in detail. The simulation model for an “ionic wind” propulsion system was established by coupling a two-dimensional gas discharge model with a gas dynamics model. The influences of electrode voltage, spacing, size, and shape on the performance of the propulsion system were investigated. The fluid-solid interaction method was used to solve static aeroelastic characteristics under deformation. The aerodynamic and thrust performances of the elastic state and the rigid state were compared. It was found that the operating voltage, the distance between two electrodes, and the emitter radius had greater impacts on the thrust of the propulsion system. The propulsion system had a small contribution to the lift but a large contribution to the drag. In the elastic state, the lift coefficient accounted for 12.2%, and the drag coefficient accounted for 25.8%. Under the action of the downwash airflow from the wing, the propulsion system formed an upward moment around the center of mass, which contributed greatly to the pitching moment derivative of the whole aircraft. In the elastic state, the pitching moment derivative accounted for 29.7%. After elastic deformation, the thrust action point moved upward by 28.7 mm. Hence, the no lift pitching moment is reduced by 0.104 N·m, and the pitching moment coefficient is reduced by 0.014, causing a great impact on the longitudinal trimming of the whole aircraft.

Development and Challenge of More/All Electric Aircraft

With the rapid development of the aviation industry and the increasing environmental concern, the electrification of aircraft has become a leading research topic in aviation. More Electric Aircraft (MEA) and All Electric Aircraft (AEA) are two classifications of this field. MEA is designed to apply electrical structures to update traditional hydraulic and mechanical equipment, so as to improve the fuel efficiency of the aircraft, while the main propulsion power is still provided by aviation fuel. This excogitation has been developed in stages and put into commercial use. AEA is a more idealized design which aims to eliminate all forms of energy other than electrical energy on the aircraft in order to achieve higher efficiency and environmental goals. Research on AEA encounters multiple technical barriers, mainly the battery energy density. This paper introduces developments on the structures involved in the electrification of aircraft and their characteristics, then systematically analyses the main technical factors that limit the development of AEA and the possible technological breakthroughs in the future.

Reliability-Based Analysis of Main Propulsion Fuel Oil System Maintenance for Tugboats with Qualitative and Quantitative Methods

This study aims to analyze the maintenance of the main propulsion fuel oil system for tugboats using both qualitative and quantitative methods. The focus is on evaluating the reliability of the system and identifying potential areas for improvement. The research employs a combination of expert interviews, industry standards, and statistical analysis to provide a comprehensive overview of the maintenance practices in place. The goal is to enhance the overall performance and longevity of the main propulsion fuel oil system in tugboats. The study uses data on the operational time, failure time and frequency, the number of vessels served, and fuel system diagrams to analyze the system's reliability. Qualitative methods such as Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA) were used, as well as quantitative methods such as Overall Equipment Effectiveness (OEE), Markovian Decision Process (MDP), and reliability methods. The study found that the FO Purifier component was the critical component with a Risk Priority Number (RPN) of 294. The average value of OEE was 47%, lower than the standard of 85%. The MDP analysis showed a probability of 0.08 for mild damage and 0.46 for moderate to severe damage under steady-state conditions. The FO Purifier component had the lowest Mean Time to Failure (MTTF) value of 1658.50 hours. The study provides a graph of the reliability function against time, and recommends maintenance actions based on the MTTF and MDP.

Decarbonizing in Maritime Transportation: Challenges and Opportunities

As global warming caused by greenhouse gases grows (GHGs) into a global environmental threat, carbon dioxide emissions are drawing increasing attention in these years. Among all emission sources, transportation is a major contributor to climate change because of its high dependence on fossil fuels. The International Maritime Organization (IMO) has therefore been promoting the reduction of fuel usage and carbon emissions for container ships by such measures as improving shipping route selection, shipping speed optimization, and constructing clean energy propulsion systems. In this paper, a review of the impact of carbon dioxide emissions on climate change is presented; the current situations of carbon dioxide emissions, decarbonizing methods, IMO regulations, and possible future directions of decarbonizing in the maritime transportation industry are also discussed. Based on the result, it is found that in the case that non intelligent ships still occupy the vast majority of operating ships, the use of new energy as the main propulsion fuel has the defects of high renewal cost and long effective period. It is more likely to achieve energy conservation and emission reduction in the shipping industry in a short period of time by using intelligent means and artificial intelligence to assist ship operation.

Feedback Linearization Controller Design for Solid Oxide Fuel Cells

Electric vehicles have attracted the attention of users because they do not burn fossil fuels and emit zero greenhouse gas emissions. Fuel cells have shown their potential to power vehicles as well. The most common fuel cell types as power sources for automobiles are i) Proton exchange membrane fuel cell (PEMFC) and ii) Solid oxide fuel cell (SOFC). Normally, the PEMFC is considered main propulsion system. On the other side, the SOFC is generally not considered for propulsion system but considered for auxiliary power unit (APU). In this paper, feedback linearization controller for solid oxide fuel cells is proposed. And the performance of proposed controller is simulated under current disturbances operation condition through Matlab simulation.

Reliability Evaluation of Electrochemical Energy Storage Systems Supplying the Ship's Main Propulsion System

Reliability Evaluation of Electrochemical Energy Storage Systems Supplying the Ship's Main Propulsion System

Modeling of pollutant emissions from the turbine engine of the main propulsion of a vessel in operating conditions

The intensification of environmental protection measures is being implemented in all economic and industrial activities. The goal of reducing harmful emissions from various types of combustion engines used in different applications is being pursued dynamically. The introduced changes concern the values of harmful emission limits and the methods of measuring or assessing their emissions. There are solutions for propulsion systems, such as turbine engines used on ships, where there is a need for constant monitoring of operational and environmental parameters during the operation of the vessels. Continuous measurement of harmful emission values contained in exhaust gases during the operation of these systems allows for an assessment of their impact on the environment. However, due to the costs of measuring equipment and limitations associated with its use, alternative methods are being sought to evaluate pollution emissions resulting from the operation of turbine engines. One possibility is to assess the emission characteristics of the propulsion system in emission tests under conditions of its actual operation. Based on this, by introducing basic mathematical tools, it is possible to determine the values of emissions of individual pollutants during the propulsion system operation in actual conditions. These actions are presented in this paper.

The rise of metal-organic framework based micromotors.

Micromotors (MMs) are micro and nanoscale devices capable of converting energy into autonomous motion. Metal-organic frameworks (MOFs) are crystalline materials that display exceptional properties such as high porosity, internal surface areas, and high biocompatibility. As such, MOFs have been used as active materials or building blocks for MMs. In this highlight, we describe the evolution of MOF-based MMs, focusing on the last 3 years. First, we covered the main propulsion mechanisms and designs, from catalytic to fuel-free MOF-based MMs. Secondly, we discuss recent applications of new fuel-free MOFs MM to give a critical overview of the current challenges of this blooming research field. The advantages and challenges discussed provide a useful guide for the design of the next generation MOF MMs toward real-world applications.

Fault detection and diagnosis for liquid rocket engines with sample imbalance based on Wasserstein generative adversarial nets and multilayer perceptron

The reliability of liquid rocket engines (LREs), which are the main propulsion device of launch vehicles, cannot be overemphasised. The development of fault detection and diagnosis (FDD) technology for LREs can effectively improve the safety and reliability of launch vehicles, which has important theoretical and engineering significance. With the rapid development of artificial intelligence technologies such as machine learning and artificial neural network, data-driven FDD methods have gained increasing attention. However, the scarcity of engine fault samples limits the application of this methods. We proposed a method combining Wasserstein generative adversarial nets (WGANs) and multilayer perceptron (MLP) to perform FDD for LREs with sample imbalance. Wasserstein generative adversarial nets were trained using the fault data from the actual hot-firing ground test of a large LRE. Considerable fault data were generated to expand the data set to balance the ratio of positive and negative samples. Subsequently, the expanded data set was used to train the MLP for FDD of a large LRE. The results showed that the samples generated by the WGAN were authentic, confirming the application of the proposed method as a novel and effective tool for establishing a complete LRE fault database. Furthermore, the diagnosis times of the proposed method on five fault tests were advanced by 0.66, 15.82, 0.24, 0.14 and 1.08 s in relation to those of the conventional red-line cut-off system. Compared with support vector machine and adaptive threshold algorithm, the proposed method also performed better.

Design of contingency point return trajectory in the lunar orbit insertion phase for crewed lunar exploration missions

To satisfy the requirement of contingency rescue in the lunar orbit insertion phase for crewed lunar exploration missions, this paper designs the contingency point return trajectory. First, according to different failure situations of the main propulsion system in the lunar orbit insertion phase, different types of contingency return modes are analyzed and summarized. Second, considering the terminal constraints of point return, a calculation model of the contingency point return trajectory is established, and a serial optimization process is adopted to obtain a high-fidelity solution. Finally, a numerical simulation is used to verify the model. The simulation results indicate that this model can be applied to determine the contingency point return trajectories under different situations in the lunar orbit insertion phase and demonstrate the validity and feasibility of the trajectory calculation model proposed in this paper. The research conclusions can provide a reference for the design of contingency rescue schemes in the lunar orbit insertion phase for crewed lunar exploration missions.

A Novel FDTD–PML Scheme for Noise Propagation Generated by Biomimetic Flapping Thrusters in the Ocean Environment

Biomimetic flapping-foil thrusters can operate efficiently while offering desirable levels of thrust required for the propulsion of a small vessel or an Autonomous Underwater Vehicle (AUV). These systems have been studied both as main propulsion devices and for augmenting ship propulsion in waves. In this work, the unsteady hydrofoil loads are used to calculate the source terms of the Ffowcs Williams–Hawkings (FW-H) equation which is applied to model noise propagation in the underwater ocean acoustic environment. The solution provided by a simplified version of the Farassat formulation in free space is extended to account for a bounded domain and an inhomogeneous medium, characterizing the sea acoustic waveguide. Assuming the simplicity azimuthal symmetry of the environmental parameters, a numerical model is developed based on a Finite Difference Time Domain (FDTD) scheme, incorporating free-surface and seabed effects, in the presence of a variable sound speed profile. For the treatment of the outgoing radiating field, a Perfectly Matched Layer (PML) technique is implemented. Numerical results are presented illustrating the applicability of the method.

Studies on the Effects of Cold Starts of the Ship Main Engine

Abstract This article presents the influence of various ship’s operational conditions occurring during manoeuvres related to entering and leaving the ports and mooring operations. Frequent starts and stops of the ship’s propulsion unit are then required, which affect the variability of the energetic loads of the ship’s power plant, causing accelerated, non-design wear of the ship’s main propulsion engine. The effects of cold start-ups of the main ship engine are the subject of this study. Conditions of the engine inlet valve damage process are discussed. The physics of the degradation process leading to air inlet valve damage was considered. Laboratory tests of structure continuity and their results are discussed, and the valve material defects were excluded as the cause of the damage. The causes of repeated damage to the inlet air valves were identified. The effectiveness of the performed corrective measures was confirmed by a documented control test of the engine start-up. The article is a utilitarian premise for the requirements of the Classification Society.

Numerical Dynamic Analysis of a Composite Pleasure Craft for Comfort Improvement

Comfort on board is one of the most important design aspects of present pleasure boats, in addition to performance and aesthetics. In order to reduce construction costs and improve quality, it is necessary to deal with vibration and noise issues in the early stages of design to obtain preliminary information about the structure's response to vibrations before the project reaches a stage in which it is difficult to make structural modifications. In this paper, the modal and harmonic analyses of a 25 m motor yacht made of composite materials are performed to investigate the structure's dynamic behavior and improve the comfort level. The numerical verification is carried out by conducting a series of dynamic analyses on a finite element model based on sequential phases and taking into account the model with and without added mass. The modal analysis is carried out for two configurations, that is the engines installed with rigid connections and with elastic connections) in order to determine all the global and local natural frequencies and to check the possibility of the occurrence of the resonance phenomenon. The harmonic analysis is executed first by applying an explorative load at the after keel line of the boat to determine the response peaks and estimate the correct damping coefficients, and secondly by applying the load generated by the main propulsion sources to verify the onboard comfort. The vibration velocity spectra obtained by the numerical model of the boat are compared with guideline limits and the results showed that the vibration velocity in different areas of the boat remains within the limit levels imposed by the British Standard ISO 20283-5:2016 concerning habitability, and the limits set by RINA Rules concerning comfort.

Выбор двигательной установки перспективного малого разгонного блока

The paper considers the selection of a main propulsion system of a small space tug, whose development is relevant due to the problem of disproportion between the existing launch vehicles and promising payloads. This problem arose in connection with the active development of multi-satellite constellations. The tendency to increase the number of operated spacecraft turned out to be dialectically related to the tendency to reduce the size of a single spacecraft. The paper introduces the results of the analysis of the functional efficiency of the transport operation and the cost analysis of the options for a small space tug. The analysis was carried out as part of the competition for the development of ultralight launch vehicles, organized by ANO Aeronet. A criterion for selecting a propulsion system for a small space tug from the point of view of efficiency is proposed. The study shows that for a small space tug weighing no more than 80 kg, designed to perform a coplanar transport operation lasting no more than three days with a payload weighing no more than 150 kg and an available reserve of delta-V budget of no more than 500 m/s, the best option is a propulsion system on gaseous oxygen — methane components, which does not require a specialized displacement system and the gas jet engines of the control system work on any of the components.

Research on Application of High-Frequency Pulse Vibration in Ship Electric Propulsion System

Aiming at the problems existing in the method of using sensors to detect the rotor position of marine main propulsion motor at low speed, a sensorless rotor position identification method based on high-frequency pulse vibration signal is proposed. In this method, the low-pass filter is used to separate the high-frequency signal component, and the current component of d-axis to q-axis is demodulated. The control mode of PI action law is used to phase-locked processing of the demodulated signal, in which purpose is to obtain the rotor position signal. The design method is simulated and verified by MATLAB/Simulink software. The error between the estimated position and the actual position of the rotor in the simulation waveform is small, and the accuracy is high. The simulation results show that this method can achieve good results when applied to the ship electric propulsion system without position sensor, which provides a theoretical reference for the design of marine main propulsion motor control system.