Propulsion Engine Research Articles

Selection of design parameters of a spacecraft electric propulsion engine ensuring the geostationary orbit raising mission

The problem of selecting suboptimal parameters of an electric propulsion system as part of a spacecraft, ensuring a geostationary orbit raising mission using a Soyuz-5 launch vehicle at the initial launch stage, is investigated. An expression is obtained for the main optimality criterion – the payload relative mass. An algorithm is obtained for solving the problem of parametric optimization of an electric propulsion system as part of a hybrid transportation system. The task of selecting the optimal electric propulsion engine for launching a spacecraft with an electric propulsion system to a geostationary orbit using the launch vehicle under consideration is solved. A design ballistic calculation and a comparative analysis of the obtained data are performed.

Interpretable Machine Learning: A Case Study on Predicting Fuel Consumption in VLGC Ship Propulsion

The integration of machine learning (ML) in marine engineering has been increasingly subjected to stringent regulatory scrutiny. While environmental regulations aim to reduce harmful emissions and energy consumption, there is also a growing demand for the interpretability of ML models to ensure their reliability and adherence to safety standards. This research highlights the need to develop models that are both transparent and comprehensible to domain experts and regulatory bodies. This paper underscores the importance of transparency in machine learning through a use case involving a VLGC ship two-stroke propulsion engine. By adhering to the CRISP-DM standard, we fostered close collaboration between marine engineers and machine learning experts to circumvent the common pitfalls of automated ML. The methodology included comprehensive data exploration, cleaning, and verification, followed by feature selection and training of linear regression and decision tree models that are not only transparent but also highly interpretable. The linear model achieved an RMSE of 23.16 and an MRAE of 14.7%, while the accuracy of decision trees ranged between 96.4% and 97.69%. This study demonstrates that machine learning models for predicting propulsion engine fuel consumption can be interpretable, adhering to regulatory requirements, while still achieving adequate predictive performance.

Methods of reducing fuel consumption by seagoing vessels in order to reduce emissions of harmful substances into the atmosphere

The aim of the paper is to draw attention to the emissions of toxic compounds into the atmosphere problem by seagoing ships. Annex VI of the MARPOL Convention, which came into force in 2005, concern the prevention of air pollution from ships, forced shipowners to use solutions aimed at limiting the emission of these harmful substances into the atmosphere. One of the instruments enabling the implementation of these guidelines is the design energy efficiency index EEDI, introduced obligatorily for designed and newly built ships. In turn from 2013, the regulations also oblige shipowners to maintain an effective energy management plan during ship's operation, SEEMP (Ship Energy Efficiency Management Plan). The paper presents factors that influence the reduction of fuel consumption by ships, leading to a reduction in emissions of harmful substances into the atmosphere and thus achieving the required EEDI and other indicators. These are factors related to the ship's hull, the main propulsion engine and the propeller-rudder system. The influence of each of these factors on the level of fuel consumption by the ship was indicated. The work highlights the methods of reducing fuel consumption by seagoing ships aimed at reducing emissions of toxic compounds into the atmosphere, which are currently the most popular and effective, and relate mainly to the hull and main propulsion engines.

Developing and testing systems for the attenuation of ships' machinery noise

With ships operating in areas including important marine biodiversity, it is crucial to understand the sources and characteristics of underwater noise and develop effective measures to mitigate underwater noise's impact on the environment. The underwater noise signature from a ship is usually dominated by machinery noise and propulsion engines at low speeds. Given the importance of onboard electrical power, diesel generators might continuously function (i.e., even when a ship is docked) and generate low-frequency underwater noise. Université de Sherbrooke (Sherbrooke, Canada) and Innovation Maritime (Rimouski, Canada) lead a collaborative work focusing on the means and methods for attenuating machinery noise. Two main research axes are considered. The first concerns the setup and validation of a small-scale platform that can be used to test noise reduction methods in a controlled water basin environment. The second research axis investigates passive, tunable, and possibly multi-resonant vibroacoustic solutions to attenuate machinery noise. These solutions mostly come as 3D-printed folded quarter-wave resonators following spiral or cantilever resonators. Acoustic resonators can also be embedded into a layer of sound-absorbing material to improve soundproofing properties at specific frequencies. The applications and scope of this work are finally put into perspective.

Ammonia Sprays for Combustion: A Review

Ammonia is a globally transported chemical used for a variety of applications, most notably, the production of fertiliser. Over the past decade, attention has been afforded to the use of ammonia as an energy carrier, coupling global supply of renewable energy to demand regions. Ammonia’s advantages as an energy carrier include its ease of liquefaction and established international transportation routes; overcoming its low reactivity, excessive production of nitrogen oxides and its toxicity remain as challenges. For energy applications, fuel delivery is a critical aspect of effective combustion in boilers, burners and engines. Due to its adaptable phase change characteristics, ammonia fuel may be injected as a liquid or vapour, each with respective advantages or disadvantages. The focus of this review concerns the characterisation of liquid ammonia fuel injection for combustion, including recent research findings from experimental and simulation studies. Liquid ammonia injection can result in the highly dynamic so-called ‘flashing’ or ‘flash boiling’ phenomena. Research findings have been drawn from other related applications such as accidental hazardous releases. Bespoke optical experimental rigs together with diagnostic techniques and two-phase computational fluid dynamics (CFD) simulations have enabled studies of the flashing jets under various initial or final conditions, with recent work also examining ammonia spray combustion. The review concludes with an insight into future trends and requirements for liquid ammonia combustion. Reciprocating engines for marine propulsion are cited as potential early adopters of ammonia energy.

Three-dimensional reconstruction of insect chemosensory sensillum

The olfactory system is involved in food and mate recognition in insects. However, 3D structures of chemosensory sensilla in insects are unexplored yet. Here, the internal structures of an olfactory sensillum on the antenna of the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae), one of the most important rice pests, are examined and imaged using focused ion beam scanning electron microscopy. Based on these images, a 3D structure is reconstructed in this study. We find that the trichoid olfactory sensillum possesses a multiporous wall encircling a lumen with one sensory cell. Besides, there are three accessory cells (ACs) and a glia cell with different cell contents surrounding the sensory cell. The abundant tubular membrane structures in the tormogen cell suggest its role in secreting proteins like odorant binding proteins into the receptor lymph, while three auxiliary cells with simpler cellular content closely enfold the sensory cell, probably to prevent leaking of the receptor lymph into the surrounding epidermis. In the sensory cell, the microtubules and two tandem basal bodies at the base of the microtubules are also reconstructed. They are considered as a propulsive engine to ensure dendrite vibration or spinning in the receptor lymph, so that the proteins and odorant molecules move faster in the receptor lymph, which improves recognition of environmental odors and enables the insect to immediately respond to this information.

Performance analysis of the adaptive cycle engine with cooling air: From propulsion performance, thermodynamic efficiency, exergy and infrared characteristics

The adaptive cycle engine gains significant attention due to its variable thermodynamic cycles and multi-duct characteristics, which are utilized for thermal management to enhance engine performance. This paper explores the features of multi-duct technology in adaptive cycle engines and aims to improve engine flight performance. An analysis is conducted on the impact of duct air bleed on engine propulsion characteristics, thermodynamic cycle properties, and exhaust system infrared radiation characteristics. Initially, a component-level model of the adaptive cycle engine was established, considering CDFS duct, bypass duct, and third duct air cooling devices. This model uses the ducted cold air to cool the temperature of low-pressure turbine exit, center cone wall, and main nozzle expansion section wall. Subsequently, a method for analyzing the infrared radiation of the engine exhaust system was proposed based on the above model, and the performance of engine components and the overall engine was analyzed in terms of energy, exergy, mechanical efficiency, and thermal efficiency. Finally, the numerical simulations of the propulsion performance, thermodynamic efficiency and infrared characteristics of the adaptive cycle engine with cooling air were carried out under conditions of ground takeoff, subsonic cruise, and supersonic cruise. The simulation results show that the cooling air can effectively enhance engine performance and infrared stealth capabilities under various flight conditions. The ducted air extraction measures proposed in the paper could effectively improve the propulsion efficiency and stealth characteristics of the engine, providing important references for the development of more efficient aeroengine.

Research on Aircraft Engines and Advanced Power in Land, Sea and Air

This paper provides a comprehensive overview of advanced propulsion technologies in military applications across land, sea, and air domains. It examines the theoretical foundations of propulsion systems, tracing the evolution of aircraft engines from early piston designs to modern jet propulsion. The study explores current state-of-the-art technologies, including advanced turbofan engines, hybrid electric systems, and nuclear propulsion for naval vessels. Special attention is given to emerging fields such as unmanned aerial vehicle propulsion, hypersonic technologies, and stealth engine designs. The research also delves into futuristic concepts like magnetohydrodynamic propulsion and pulse detonation engines. Throughout the analysis, common themes of improved efficiency, enhanced power-to-weight ratios, and increased operational capabilities are highlighted. This paper aims to provide a holistic view of the current landscape and future trajectory of military propulsion technologies, underlining their critical role in shaping modern warfare capabilities.

Vimanas: Bridging Modern Aerospace Innovations with Ancient Spacecraft Technologies

The TV show Ancient Aliens on the HISTORY channel experimented with an ancient VIMANA model in a wind tunnel and found that it produced lift. This event sparked curiosity among people unaware of ancient Indian technologies. This paper reviews the technologies purportedly utilized in ancient Indian airplanes, as described in the Vedas. These texts frequently referenced various technologies resembling those used in contemporary aircraft and included myths and traditions about Hindu gods. Shivkar Talpade, an Indian with a strong interest in aviation, was inspired by these accounts. He later built and piloted an aircraft called Marutsakha, using mercury as fuel. Additionally, the Rukma Vimana has been cited as an inspiration for SpaceX's Crew Dragon module. These ancient aviation concepts share similarities with modern ideas, such as ion propulsion engines, antigravity aircraft, and stealth technologies. Research on vimanas has been made possible by translating old manuscripts into modern languages. The aim of current research is to inspire the younger generation to revive the nation's glory through scientific inquiry.

Evaluating long-term operational data of a Very Large Crude Carrier: Assessing the diesel engines waste heat potential for integrating ORC systems

Given the spotlight on waste heat recovery (WHR) technologies for decarbonizing the shipping industry, critically assessing waste heat from propulsion and auxiliary engines using actual data is crucial for accurately predicting fuel and carbon savings. This paper addresses this by applying advanced data processing, considering voyage characteristics, and developing methods for mapping waste heat from main engine (ME) and diesel gensets (DGs) operations using long-term operational data from a Very Large Crude Carrier (VLCC) case study. Two methods predict unrecorded air mass flows by implementing heat balance: one using measured temperature values and the other estimating exhaust gas mass flow rates based on fuel oil consumption. Within the main objectives of this study is to examine the impacts of employing the exhaust gases of both ME and DGs to evaporate recuperative ORC working fluid on power output and vessel annual carbon savings, with the formed diesel engines operational profiles serving as inputs. Simulations show a power output of 530 kW using ME exhaust gases, increasing to 653 kW and 741 kW with DGs integration for R245fa and R1233zd(E) as the selected ORC working fluids, respectively. The proposed solutions can reduce annual CO2 emissions by 4 % to 7 %.

Evaluation of the Teaching-Learning Process of Gas Turbine Engine Fundamental Using Generic Features of Good Teaching

Understanding gas turbine engines as aircraft propulsion engines is essential in aircraft maintenance. It was found that the learning outcomes for basic turbine motor courses (gas turbine engine fundamentals) were not optimal. This research aims to learn and teach basic motorbike courses that focus on finding out learning activities based on the general features of good teaching Gall et al. (2007) in the basic course on turbine motors at the TPU D.IV Study Program. This research was conducted in June-July 2022 and used qualitative methods with semi-structured interviews, observations, and theoretical studies to collect qualitative data. Six findings, namely lack of student involvement; activity plans inside and outside lectures are inadequate; need to maintain and plan better practical activities; no program for implementing understanding in the classroom; and emphasis on activities in pairs or groups. The limitation of this research is that it only examines teaching and learning activities. There may be other parameters that can influence academic achievements such as student characteristics, availability of learning materials, facilities, etc., or developing learning with a structured active learning approach to maintain student involvement and understanding of the content that needs to be carried out in further research.

Experimental study on Camless compressed air engine port timing using electronic control unit

This research paper presents an experimental study conducted on an air engine with an electronic control unit (ECU) to investigate the influence of inlet pressure on port timing. Traditional air engines use mechanical camshafts to control valve timing, but camless air engines use solenoid valves controlled by an ECU for more precise control. The study compares variations in intake sustains angle (ISA) and exhaust advance angle (EAA) to determine their impact on engine performance. The results show that ISA has a more significant influence on work performance and work done compared to EAA. The study also identifies the optimal ISA for different intake pressures, showing that higher ISA is beneficial at low intake pressure, while lower ISA is preferable with increasing pressure. Overall optimal ISA increases an average 12 % percentage efficiency of the air engine compared to the change in EAA. This research provides valuable insights for designing and developing non-polluting propulsion engine systems and optimizing the design of air engines for improved performance, fuel efficiency, and lower emissions.

Home-Based Rocket Design and Fuel Project

This detailed research paper delves into the practicality and step-by-step process of creating a small-scale rocket and manufacturing its fuel from scratch within a home setting. The main objective of this study is to furnish a thorough manual for individuals passionate about amateur rocketry, emphasizing the importance of safety measures, materials, design concepts, and fuel composition. The project showcases the educational and experimental possibilities of rocketry in a domestic context, which can enhance knowledge of propulsion science and engineering fundamentals.

Overall scheme design of a closed solid oxide fuel cell hybrid engine for ships

A scheme of compact closed solid oxide fuel cell hybrid engines for ship power and propulsion on ships is proposed. A zero-emission closed engine at the effective equivalence ratio of 1 is achieved by recirculating water and fuelling by liquid hydrocarbon fuel and oxygen. The adiabatic pure oxygen reforming temperature of the reformer is higher than the specified anode inlet temperature. A turbine is placed in front of the solid oxide fuel cell anode. Detailed potential distributions are considered using a two-dimensional solid oxide fuel cell model, and thermodynamic models of the hybrid engine are built. The performance of the reformer is more sensitive to the oxygen-carbon ratio rather than the steam-carbon ratio, which leads to a huge change of the pressure ratio of the turbine. Therefore, the power ratios of turbines and SOFC are also affected by the oxygen and steam carbon ratio and excess oxygen coefficient. The optimized power ratio is 1.02–1.13, which results in a significant change in the efficiency of the engine. Under the specified operating conditions, the engine can achieve a high efficiency of 67 %. Under the off-design conditions, with the increase of the mass flow of fuel or the current density, the power of the engine can be changed from 20 % to 160 % of the designed power.

Control system optimisation of biodiesel-based gas turbine for ship propulsion

<p>Reducing a gas emission of shipping transportations become a main goal of international maritime organization to achieve a clean energy. One of best scenarios to achieve this goal is to shift a fossil fuel to a renewable energy-based fuel of a ship propulsion. This paper studies an optimization of a control system of the renewable-based small gas turbine engine for the ship propulsion. Proposed control system consists of a proportional-integral with engine performance limiters to avoid an engine damage. Proportional-integral gains are tuned by a whale optimization algorithm. A gain scheduling analysis of a step response is performed to obtain a searching area of tuning parameters and values of constant gains. In this step, the gains are modeled as function of plant variables. After the searching area is obtained, the proportional-integral gains are optimized using the whale optimization algorithm while the additional gains are set as constant values. Using this scenario, stable and optimal gains have been successfully achieved. Results show that the proposed method has better performance than that of the previous methods, i.e. gain scheduling and gain scheduling optimized by the whale optimization algorithm. The proposed method has lowest fitness value and does not have an overshoot problem.</p>

Development of SunVoyager Interstellar Precursor Probe Driven by Inertial Confinement Fusion Propulsion

In this paper, we present updated calculations for the SunVoyager probe, a spacecraft conceptual design for a mission to the outer solar heliosphere to a distance of 500–1000 AU, in a trip time of ∼6–10 years traveling at speeds of 720 km/s. The spacecraft is innovative, in that it uses an inertial confinement fusion propulsion engine driving a 5.76-mg pellet filled with D3He fuel detonated at 10-Hz pulse frequency, augmented with 10-mg/pellet expellant propellant for enhanced mass flow rate. The spacecraft is designed to carry a 100-ton payload to include large optical telescopes for long-range imaging of nearby exoplanets. This paper is a follow-up to the earlier one that scoped out the design space, and here we give details on a more refined design configuration, in addition to calculations relating to the pellet ignition design and laser driver with 43.5 MJ delivered to the target. We also describe the power cycle with a jet efficiency of 37.8%, for a jet power of 2.67 GW and a specific power of 3.72 kW/kg.

Characteristic Investigation of a Novel Aircraft SOFC/GT Hybrid System under Varying Operational Parameters

In this study, the implementation of a solid oxide fuel cell–gas turbine hybrid engine for primary propulsion and electric power generation in aircraft is investigated. The following three parameters, which are crucial in attaining optimal performance at any point in the flight profile, were identified: the oxygen-to-carbon ratio of the catalytic partial oxidation reformer, the fuel utilization factor of the fuel cell, and the airflow split ratio at the outlet of the high-pressure compressor. The study assesses the impact of varying these parameters within specified ranges on the performance of the hybrid system. At the design point, the system yielded a total power output of 1.96 MW, with 102.5 kW of electric power coming from the fuel cell and 7.9 kN (1.86 MW) of thrust power coming from the gas turbine. The results indicate that varying the oxygen-to-carbon ratio affected the fuel cell’s fuel utilization and resulted in a slight decrease in gas turbine thrust. The fuel utilization factor primarily affected the power output of the fuel cell stack, with a minor impact on thrust. Notably, varying the airflow split ratio showed the most significant influence on the overall system performance. This analysis provides insights into the system’s sensitivities and contributes to the development of more sustainable aircraft energy systems.

CerAMfacturing of a ceramic aerospike engine

High-performance ceramics are recognized as key enabling materials because of their very high thermal, chemical and mechanical resistance in combination with a lower density compared to most metals. These properties apparently predestine ceramics for many different applications, e.g. propulsion engines.Within the present work, the high potential of additive manufacturing in the field of ceramic materials (CerAMfacturing) could be demonstrated. It is possible to produce high-resolution ceramic aerospike engines using CerAM VPP. The manufactured components not only combine the typical ceramic properties, but also exhibit:- high geometric complexity,- very good surface properties, and- very good manufacturing accuracy.These developments will pave the way for a new generation of propulsion engines.

Investigation of Charging Technologies for Electric Vehicles

In today's world, internal combustion engine vehicles are widely used. These vehicles cause harmful emissions as they use fossil fuels for engine propulsion and vehicle movement. To address this issue, electric vehicles have been considered as a solution. In electric vehicles, electric motors are used instead of traditional internal combustion engines and the necessary electrical energy is supplied from battery packs. In this way, electric vehicles do not cause harmful emissions to the environment. If the energy required for electric vehicle charging stations is obtained from renewable energy systems, electric vehicles will be zero-emission vehicles. Battery packs, that provide energy for electric vehicles, typically consist of rechargeable Lithium-ion battery groups and they can be charged using fast charging technology. In this study, the future of transportation, electric vehicles and the standards and technologies used in electric vehicle charging stations have been examined. Additionally, an electric vehicle system has been designed using MATLAB/Simscape.

Programming self-assembling magnetic microrobots with multiple physical and chemical intelligence

Medical microrobots represent the cutting-edge of biomedical research, showcasing their potential as versatile tools. They exhibit promise in acting as carriers for cancer cell therapy, effectively delivering drugs, and as manipulators equipped for biosensing, offering mobility and adaptability. Despite these advancements, the intricate challenge of creating a microrobot that seamlessly integrates various physical and chemical functionalities persists. This includes the fusion of selective sensing, manipulation capabilities, carrier functionality, precise time-based actuators for motion control, and adaptive shaping. Addressing these complexities remains an ongoing endeavor. In this context, our work introduces a pioneering magnetic microrobot founded on CaCO3 microparticles (MPs) synthesized alongside polyethylenimine (CaCO3-PEI), forming the core body. This is combined with Fe3O4 nanoparticles (NPs) enveloped in glutaraldehyde (Fe3O4-Glu), constituting the propulsive engine. The synergy of these elements enables the microrobot to execute multimodal motions, orchestrating its movement with finesse. This dynamic capability follows a “deliver-and-return” pattern for precise targeting applications with real-world relevance. Furthermore, the Fe3O4-Glu/CaCO3-PEI microrobots demonstrated remarkable proficiency in the targeted identification, manipulation, and transportation of cancer cells through the strategic integration of specific antibodies onto their structure. Within the realm of selective cancer cell detection, these microrobots adeptly function as dynamic mobile immunosensors. The versatile utility of the Fe3O4-Glu/CaCO3-PEI microrobots extends to their role as carriers for drugs and imaging agents, facilitated by the mediation of extracellular pH modulation in cancer cells orchestrated by CaCO3. This innovative work introduces a novel “on-the-fly” concept, revolutionizing the landscape of robotics programmed with multifaceted chemical and physical intelligences.