Energy Efficient Propulsion Research Articles

Advancements in Emission Reduction Technologies for the Maritime Industry a Comprehensive Analysis

This peer-reviewed scholarly article delves into recent progress in emission reduction technologies within the maritime domain, highlighting the necessity of a comprehensive and all-encompassing assessment. With its substantial role in global commerce, the maritime sector confronts escalating environmental hurdles due to its significant pollution output. The research investigates three primary technological advancements: exhaust gas scrubbers, alternative fuels like LNG, biofuels, and hydrogen, and energy-efficient propulsion systems encompassing hybrid, electric, and wind-assisted solutions. Each technology undergoes scrutiny concerning its efficacy, economic viability, and environmental benefits, complemented by tables for elucidation. Furthermore, the research briefly touches on evolving regulatory frameworks shaping the adoption of these technologies. By amalgamating these insights, the research underscores the crucial significance of a holistic strategy in steering the maritime industry toward sustainable practices and curbing its environmental impact

The Growth Engine Concept and Its Potential for an Electrified Aviation Future

Abstract The emerging need for cost- and energy-efficient propulsion systems have shifted the research interest to radical concepts, with several challenges to overcome in order to enter into service. However, revitalizing old yet provably successful engine designs—a practice followed by engine manufacturers over the years—can provide low-risk alternative solutions to move immediate market demands. The paper reviews this approach, known as concept of growth engines or core commonality, and investigates how a geometrically fixed or geometrically similar engine core can be utilized across a family of engines. The development programs of the highly successful CFM56 and PT6 engine families are analyzed, proving the success of this concept over the years. The idea is based on the engineering paradigm of product families and is briefly presented from a theoretical perspective. Implementation methods and simulation tools to initiate, conceptualize, design, and evaluate an engine family program are reviewed. The potential application of engine core commonality into electrified propulsion systems is investigated. Design challenges and opportunities that electrification imposes to the growth engine concept are discussed. Finally, the concept of growth electrified propulsion systems is introduced, conveying future research directions to achieve a successful family of engines for electrified applications.

Side Fins Performance in Biomimetic Unmanned Underwater Vehicle

This paper presents the experimental research conducted for the Biomimetic Unmanned Underwater Vehicle (BUUV). The study’s major goal is to create a single, flexible side fin with adequate proportions and stiffness for an energy-efficient propulsion system. The experiments were carried out in a laboratory water tunnel equipped with a sensor for direct thrust measurement for various fin dimensions. Further, the particle image velocimetry (PIV) approach was used for a more in-depth examination of fluid–structure interaction (FSI) phenomena. The given experiments indicate the region of superior propulsion system performance and explain the main aspects that have influenced thrust generation using image processing and the PIV approach.

Marine turtles are only minimally sexually size dimorphic, a pattern that is distinct from most nonmarine aquatic turtles.

Turtles have been prominent subjects of sexual size dimorphism (SSD) analyses due to their compact taxonomy, mating systems, and habitat diversity. In prior studies, marine turtles were grouped with fully aquatic non‐marine turtles (NMATs). This is interesting because it is well‐established that the marine environment imposes a distinct selective milieu on body form of vagile vertebrates, driven by convergent adaptations for energy‐efficient propulsion and drag reduction. We generated a comprehensive database of adult marine turtle body sizes (38,569 observations across all species), which we then used to evaluate the magnitude of SSD in marine turtles and how it compares to SSD in NMAT. We find that marine turtles are only minimally sexually size dimorphic, whereas NMAT typically exhibit female‐biased SSD. We argue that the reason for this difference is the sustained long‐distance swimming that characterizes marine turtle ecology, which entails significant energetic costs incurred by both sexes. Hence, the ability of either sex to allocate proportionately more to growth than the other is likely constrained, meaning that sexual differences in growth and resultant body size are not possible. Consequently, grouping marine turtles with NMAT dilutes the statistical signature of different kinds of selection on SSD and should be avoided in future studies.

Effect of body stiffness distribution on larval fish-like efficient undulatory swimming.

Energy-efficient propulsion is a critical design target for robotic swimmers. Although previous studies have pointed out the importance of nonuniform body bending stiffness distribution (k) in improving the undulatory swimming efficiency of adult fish-like robots in the inertial flow regime, whether such an elastic mechanism is beneficial in the intermediate flow regime remains elusive. Hence, we develop a class of untethered soft milliswimmers consisting of a magnetic composite head and a passive elastic body with different k These robots realize larval zebrafish-like undulatory swimming at the same scale. Investigations reveal that uniform k and high swimming frequency (60 to 100 Hz) are favorable to improve their efficiency. A shape memory polymer-based milliswimmer with tunable k on the fly confirms such findings. Such acquired knowledge can guide the design of energy-efficient leading edge-driven soft undulatory milliswimmers for future environmental and biomedical applications in the same flow regime.

Hypergolic combustion of boron based propellants

We investigate the potential of sodium borohydride (NaBH4) as reactive additive for ignition and combustion of boron and boron-paraffin wax solid fuels using hydrogen peroxide (H2O2) as liquid oxidizer. The new hybrid propellant system (solid fuel and liquid oxidizer) is investigated for a gas generator in ducted ramjets in which, the fuel-rich hot gases would be used for ramjet. Measurements of ignition delays along with visualizations of the ignition and combustion events were conducted by high-speed imaging on three propellant configurations; oxidizer drop on boron powder, oxidizer drop on boron-paraffin solid fuel slab, and oxidizer spray on a hollow cylindrical boron-paraffin fuel grain. These investigations revealed that the hypergolicity of boron with H2O2 is controlled by catalytically driven exothermic decomposition of H2O2 into superheated steam and oxygen in the presence of magnesium (∼5%) such that ignition and combustion of boron is delayed inordinately (7 s at 1.0 MPa). Boron hypergolicity improved dramatically by adding only 1% NaBH4 due to higher exothermicity of NaBH4H2O2 reaction. This reaction driven hypergolicity is very fast (∼1 ms at 1.0 MPa), rapidly gasifies boron oxide layer, and enables sustained combustion of boron. Ignition of boron-paraffin wax solid fuel slab with a single drop of oxidizer was achieved with mean delay ∼5.4 ms at 1.0 MPa. The optimum NaBH4 concentration (5.7 wt%) for achieving ignition and spontaneous burning of boron was evaluated as a baseline formulation. The spray-on-hollow cylindrical fuel grain achieved combustion of boron during ignition and reignition tests with an ignition delay of 12–15 ms under normal ambient conditions. Our investigations prove the feasibility of utilizing liquid H2O2 for the hypergolic combustion of boron based solid fuels for a green and energy efficient propulsion system.

Evaluation of energy efficient propulsion technologies for unmanned aerial vehicles

The transition to cleaner, more efficient and longer-endurance aircraft is at the forefront of research and development in air vehicles. The focus of this research is to experimentally evaluate hybrid propulsion and energy harvesting systems in unmanned aerial vehicles (UAVs). Hybrid systems offer benefits over conventional gasoline and electric systems including lower environmental impacts, reduced fuel consumption, redundancy, and distributed propulsion. Additional energy efficiency can be achieved by harvesting some of the thermal energy of the exhaust gases. The development and experimental evaluation of a hybrid propulsion UAV was carried out at the University of Victoria Center for Aerospace Research (UVIC-CfAR) in the framework of the Green Aviation Research & Development Network (GARDN) grant. The work involved the development of a framework to evaluate UAV hybrid propulsion efficiency, and to predict the amount of power harvestable from thermoelectric generators (TEGs). The objective was to combine all of the components into a modular test bench that will allow the performance of the parallel hybrid system to be characterized and compared with theoretical results. Several experiments were performed to collect performance data of various components including a triple-TEG system connected to an engine, and system variables were modified to simulate flight profiles.

Energy Efficient Small Inland Passenger Shuttle Ferry with Hybrid Propulsion - Concept Design, Calculations and Model Tests

Abstract In recent years, there has been a significant development in “green” and energy efficient propulsion systems, which fits into the general trend of environmentally friendly “green shipping”. The pursued goal is to construct a safe passenger ship that is low in energy demand and equipped with a highly energy efficient, emission-free propulsion system. The paper presents main problems encountered by designers of a small, hybrid-powered ferry powered lithium batteries. The conducted research allowed to create a design of an energy efficient hull shape, which decreases the demand for energy. Completed remote control model tests resulted in a proposal of an energy efficient and safe propulsion system with good manoeuvring capabilities. Measurements completed on an existing ferry permitted completing energy balance and forming an energy management policy. The paper contains the emission calculations computed for the existing ferry that are necessary for the environmental impact analysis. The soon to be constructed, newly designed vessel will provide a valuable contribution to hybrid-propulsion, energy management and unmanned technologies research.

The concept of a quiet undulating propulsion with ionic polymer-metal composites in autonomous underwater vehicles

Purpose: Recent years have shown a dynamic development of underwater robotics. Autonomous biomimetic underwater vehicles (BUVs) with undulating propulsion are the latest branch in this area. They imitate not only the construction of underwater living organisms such as fish, but also kinematics of their motion. Such solution gives more energy efficient propulsion with less noise comparing to classical propulsion based on screw propellers [1]. However even the latest solutions still use the same electromagnetic engines to drive those sophisticated constructions. This article contains the concept of a ionic polymer-metal composites drive, design for undulating propulsion. Design/methodology/approach: Design of the new type of fin requires further tests and presented model takes under the consideration influence of only few factors described in this paper. Findings: Results of the research confirm theoretical behaviour of IPMC’s (Ionic Polymer- Metal Composites) and show some disadvantages of this type of materials. Research limitations/implications: The effects of the research are limited to macroscopic observation with limited accuracy. Practical implications: Results of the research show possible future application of IPMC’s (in underwater robotics). Originality/value: Results of this research opens a new idea which with further tests may result in developing a new quiet undulating propulsion for BUV’s.

Fuel Effective Photonic Propulsion

With the entry of miniaturization in electronics and ultra-small light-weight materials, energy efficient propulsion techniques for space travel can soon be possible. We need to go for such high speeds so that the generation’s time long interstellar missions can be done in incredibly short time. Also renewable energy like sunlight, nuclear energy can be used for propulsion instead of fuel. These propulsion techniques are being worked on currently. The recently proposed photon propulsion concepts are reviewed, that utilize momentum of photons generated by sunlight or onboard photon generators, such as blackbody radiation or lasers, powered by nuclear or solar power. With the understanding of nuclear photonic propulsion, in this paper, a rough estimate of nuclear fuel required to achieve the escape velocity of Earth is done. An overview of the IKAROS space mission for interplanetary travel by JAXA, that was successful in demonstrating that photonic propulsion works and also generated additional solar power on board, is provided; which can be used as a case study. An extension of this idea for interstellar travel, termed as ‘Star Shot’, aims to send a nanocraft to an exoplanet in the nearest star system, which could be potentially habitable. A brief overview of the idea is presented.

Energy-Efficient Surface Propulsion Inspired by Whirligig Beetles

The whirligig beetle, claimed to be one of the most energy-efficient swimmers in the animal kingdom, has evolved a series of propulsion strategies that may serve as a source of inspiration for the design of propulsion mechanisms for energy-efficient surface swimming. In this paper, we introduce a robot platform that was developed to test an energy-efficient propulsion mechanism inspired by the whirligig beetle. A propulsor-body-fluid interaction dynamics model is proposed, and based on this model, the propulsor flexural rigidity and beating patterns are optimized in order to achieve energy-efficient linear swimming and turning. The optimization results indicate that a propulsor with decreasing flexural rigidity enhances vortex shedding and improves thrust generation. It has also been found that an alternating asymmetrical beating sequence and optimal beating frequency of 0.71 Hz improves propulsion efficiency for linear swimming of the robot. The alternating beating of the outboard propulsors and the unfolded inboard propulsors working as brakes results in efficient turning with a smaller turning radius. Both simulation and experimental studies were conducted, and the results illustrate that decreasing flexural rigidity along the propulsor length, an oscillating body motion, and an S -shaped trajectory are critical for energy-efficient propulsion of the robot.

A practical method for predicting the propulsive performance of energy efficient ship with wave devouring hydrofoils at actual seas

The Energy Efficiency Design Index (EEDI) is made mandatory by the International Maritime Organization to reduce emissions of greenhouse gases from international shipping. In this study, wave energy recovery using a pair of hydrofoils fixed at the ship bow to realize energy efficient propulsion is proposed. This so-called wave devouring hydrofoil (WDH) functions both as an anti-motion fin and a wave energy device, which can help reduce the ship wave added resistance, heave and pitch responses. To evaluate its performance, the coupled interaction between the hydrofoils and the ship under head sea condition is first modeled in the frequency domain together with the evaluation of wave added resistance in the presence of the WDHs. Model test is then conducted using a sample containership. Both the beneficial effect of the WDHs and the validity of the numerical model are proved. The peak response is reduced by 80%, 30% and 25% for added resistance, heave and pitch, respectively. This model is then further modified to include other wave directions. Based on frequency domain results, short-term and long term predictions of speed loss, engine power increase and propeller racing are performed for a 3100TEU containership along her transportation route. The merit of this prediction model is that the hull -propeller -engine interactions is considered from a system balance point of view. It is demonstrated that the WDHs can contribute to the energy-efficient ship propulsion at actual seas, achieving a slight reduction of EEDI and ensuring less speed loss and propeller racing.

Construction and evaluation of bacteria-driven liposome

Many people proposed living things as actuators, for example microbes, cell and protein molecules. To address these problems for biomedical application, especially drug delivery system, a novel, miniature, and energy-efficient propulsion concept is proposed in this paper. Some bacteria have flagellar motor for swimming in water environment. The bacterial flagellar motor is a molecular machine that converts ion-motive force into mechanical force. Liposome is well known component for drug delivery. This vesicle can contain biologically active compounds. We proposed a new integration method of these two functions, bacteria motility and liposome carrier. Bacteria and liposome are combined through antibody binding technique and we have created a bacteria-driven liposome easily. Consequently, the effect of antibody when bacteria attached to liposome is studied experimentally. Furthermore, the stochastic nature of bacterial bio propulsion of liposome is investigated. It is shown that the mobility of liposome with bacteria was higher than that of liposome without bacteria and demonstrate potential for highly-functional drug delivery system.

Swimming Behavior Analysis Based on Bacterial Chemotaxis in Solution

Microrobots is playing more and more important roles for medical applications, such as targeting tumoral lesions for therapeutic purposes, Minimally Invasive Surgery (MIS) and highly localized drug delivery. However, energy efficient propulsion system poses significant challenges for the implementation of such mobile robots. Flagellated chemotactic bacteria can be used as an effective integrated propulsion system for microrobots. In this paper, we proposed a new type of propulsion method that is inspired by the motility mechanism of flagellated chemotactic bacteria in different pH gradients. The pH gradient field was established in solution through electrolysis method. The distribution of the pH values in solution was measured with pH indicator and analyzed with image processing technology, and the mechanism by which the pH values changed was also discussed. The swimming speed and direction of the bacteria were studied experimentally. Through analyzing the key parameters, such as stabilization time and electrode voltage, the optimal design of propulsion mechanism based on bacteria motion in the pH gradient field was proven.

Application-optimised propulsion systems for energy-efficient operation

Today, optimal propellers are designed by using advanced numerical methods. Major revolutionary improvements cannot be expected. More essential are the design conditions and the optimal adaptation of the propulsion system according to the operational requirements. The selection and optimisation of the propulsion system based on a systematic analysis of the ship’s requirements and the operation profile are the prerequisites for reliable and energy-efficient propulsion. Solutions are presented, which accommodate these issues with a focus on steerable rudderpropellers. Considerations include the efficiency potential of the propulsor itself, optimisation of the engine propeller interaction, and optimisation of a demandresponsive energy supply. The propeller-thruster interaction is complex, but offers some potential for optimisation. Results of examinations show this. The power distribution between multiple propellers at high loads of limited propeller diameters increases the efficiency. This can be done by double-propeller systems like the SCHOTTEL TwinPropeller or by distributing the power on several thrusters. This distributed propulsion offers economic operation and an increased lifetime by means of the demandresponsive use of energy. An efficiency-optimized electric motor instead of the upper gear box reduces the mechanical losses in the case of diesel-electric propulsion. An example: the SCHOTTEL CombiDrive.

A Biomimetic Spermatozoa Propulsion Method for Interventional Micro Robot

Nowadays, studies of the interventional micro robots have been hot topics in the field of medical device. The ultimate goal of medical micro robots is to reach currently inaccessible areas of the human body and carry out a host of complex operations such as minimally invasive surgery (MIS), highly localized drug delivery and opening up the blood vessels. Miniature, safe and energy efficient propulsion systems hold the key to mature this technology. In this paper, a prototype of endovascular micro robot based on the motion principle of spermatozoa is presented. The properties of this propulsive mechanism are estimated by modeling the dynamics of the swimming methods. In order to validate the theoretical results for spermatozoa propulsion, a scaled-up prototype of the swimming robot is fabricated and characterized in imitative bio-pipes full of silicone oil. Experimental results shown that the spermatozoa-like micro robot can be controlled to swim efficiently. And to adjust the rotation direction of the four flexible tails, the propulsion forces and the function of opening up the blood vessels will be generated.

Design Methodology for Biomimetic Propulsion of Miniature Swimming Robots

Miniature and energy-efficient propulsion systems hold the key to maturing the technology of swimming microrobots. In this paper, two new methods of propulsion inspired by the motility mechanism of prokaryotic and eukaryotic microorganisms are proposed. Hydrodynamic models for each of the two methods are developed, and the optimized design parameters for each of the two propulsion modes are demonstrated. To validate the theoretical result for the prokaryotic flagellar motion, a scaled-up prototype of the robot is fabricated and tested in silicone oil, using the Buckingham PI theorem for scaling. The proposed propulsion methods are appropriate for the swimming robots that are intended to swim in low-velocity fluids.