MHD Accelerator Research Articles

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.

Experimental and numerical analysis of 3D end effects in Naval Magnetohydrodynamic propulsion motors

This study explores the impact of end electric current on the performance of a marine magnetohydrodynamic (MHD) propulsion motor or thruster using a comprehensive 3D numerical simulation. The investigation focuses on various operating parameters, such as electromagnetic and drag forces, efficiency, losses, current, and different pressure components. To validate the numerical findings, a scaled-down experimental setup is utilised. The results demonstrate that certain operating parameters of MHD motors are not affected by the three-dimensional characteristics of their channels. These parameters, including fluid velocity, can be accurately calculated using the analytical model based on the effective electric current of the motor. Conversely, other operating parameters of MHD motors are significantly influenced by the end effects in their channels. For example, the overall efficiency, which depends on the total electric current of the motor, should be calculated using a more precise simulation method.

Jump-starting Relativistic Flows and the M87 Jet

We point out the dominant importance of plasma injection effects of relativistic winds from pulsars and black holes. We demonstrate that outside the light cylinder, the magnetically dominated outflows sliding along the helical magnetic field move nearly radially with very large Lorentz factors, γ 0 ≫ 1, imprinted into the flow during pair production within the gaps. Only at larger distances, r ≥ γ 0(c/Ω), does MHD acceleration Γ ∝ r take over. As a result, Blandford–Znajek (BZ)-driven outflows produce spine-brightened images. The best-resolved case of the jet in M87 shows both edge-brightened features, as well as weaker spine-brightened features. Only the spine-brightened component can be BZ driven/originate from the black hole's magnetosphere.

Magnetohydrodynamic thermo-bioconvective flow of 3D rotating Williamson nanofluid with Arrhenius activation energy in a Darcy–Forchheimer medium over an exponentially stretching Surface

This paper aims to analyze the heat and mass transfer characteristics of the 3D thermo-bioconvective flow of rotating Williamson nanofluid over an exponentially stretching vertical sheet. The flow distribution considers the influence of nonlinear thermal radiation, Hall and ion-slip currents, joule heating, coupled effects of Dufour and Soret diffusion, internal heat generation, Arrhenius activation energy, Brownian, and thermophoresis diffusion in a Darcy–Forchheimer porous medium. The modeled partial differential equations (PDE) in terms of continuity, momentum, energy, concentration, and density of motile microorganisms are reformed into ordinary differential equations (ODE) forms employing similarity variables. The resulting equations are solved numerically using the spectral local linearization method (SLLM). The successive over-relaxation technique is applied to accelerate and enhance the convergence of the method. The obtained results are graphically and tabularly represented and numerically explored for the effects of pertinent parameters on the velocity, temperature, nanoparticle concentration, and motile microorganism concentration profiles. The rotation and mixed convection parameters dropped the primary velocity curve, while the Williamson and heat source parameters uplifted the microbes density distributions. The temperature field rises with an increase in radiation and microbes Brownian motion and declines with an increase in Hall and ion-slip numbers. Furthermore, with the increase in activation energy from 0.5 to 2 and the mixed convection parameter from 0.6 to 1.3, we observe a respective 3.93% rise and 8.30% fall in mass transfer rates. The current investigation has broad applications, including MHD accelerators, biotechnology, the formation of elastic sheets, the production of polymer solutions, and the synthesis of nanoparticles through microbial processes.

Numerical analysis of the self-propulsion performance of seawater MHD propulsion underwater vehicle

Numerical analysis of the self-propulsion performance of seawater MHD propulsion underwater vehicle

The Phase Modulating Micro-Mover Based on the MHD/MET System in the Reference Arm of the Scanning Interferometer

The possibility of using a magnetohydrodynamic drive (MHD) and amolecular-electronic transfer (MET) sensor as a single device for moving and precise control of the displacement of a movable mirror, which is part of a scanning interferometer, is considered. A prototype of such a device was developed and experimentally studied. A digital holographic image of the test object was obtained using an optical scheme containing a scanning interferometer with an MHD drive. The important advantages of the MHD drive in the problems of digital recording of hyperspectral holographic images have been discussed.

Analysis of MHD Falkner–Skan Boundary Layer Flow and Heat Transfer Due to Symmetric Dynamic Wedge: A Numerical Study via the SCA-SQP-ANN Technique

This article considers Falkner–Skan flow over a dynamic and symmetric wedge under the influence of a magnetic field. The Hall effect on a magnetic field is negligible for small magnetic Reynolds numbers. The magnetic field B(x) is considered over x-axis, which is in line with the wedge i.e., parallel, while the flow is transverse over the y-axis. This study has numerous device-centric applications in engineering, such as power generators, cooling reactor and heat exchanger design, and MHD accelerators. The Third and second-ordered ordinary differential equations characterize the system. A novel hybrid computational technique is designed for the surrogate solutions of the Falkner–Skan flow system. The designed technique is based on the sine–cosine optimization algorithm and sequential quadratic programming. Reference solutions are calculated by using the Runge–Kutta numerical technique. Performance matrices evaluate the accuracy and stability of our surrogate solutions, mean-absolute deviation (MAD), root-mean-square error (RMSE), and error in Nash-–Sutcliffe efficiency (ENSE). Furthermore, graphical representations in terms of convergence graphs, mesh graphs, stem graphs, stairs plots, and boxplots are presented to establish the symmetry, reliability, and validity of our solutions.

헬리컬형 자기유체역학(MHD) 해수 추진기 소형 성능시험장치 개발

A magnetohydrodynamic (MHD) seawater propulsion thruster has been proposed to reduce propeller noise, propeller pitting, and vessel vibration originated from the propeller cavitation. The MHD thruster was also focused to overcome the limitation of propulsion velocity for the special purpose of marine ships. The research trends and key technologies in the worldwide leading countries are reviewed for the development of MHD propulsion thrusters in Korea. A small performance test device was developed firstly with a conventional solenoid magnet of ≤0.6 Tesla and a helical-type cylindrical duct(inner diameter of 5 cm) of thruster. The artificial seawater was fabricated by a salt solution including a conductivity of 5~6 S/m. The measured flow velocity of artificial seawater in the test device was 0.03~0.42 m/s (0.06~0.84 Knot) with a magnetic field strength of 0.6 Tesla and the applied currents of 10~80 A including the change of anode materials. It was found that the flow direction of seawater was reversed by the directional change of applied current in the solenoid magnet.

Analysis of Effect of Inclined Magnetic Field on MHD Boundary Layer Flow over a Porous Exponentially Stretching Sheet Subject to Thermal Radiation

MHD flow has a wide range of industrial applications such as MHD propulsion for space exploration, cooling of nuclear reactors, electronic packages, microelectronic devices, and many more. Due to this, a study on the MHD boundary layer flow of a viscous incompressible fluid over an exponentially stretching sheet with an inclined magnetic field in presence of thermal radiation is analyzed. The continuity, momentum, and energy equations governing the fluid motion are obtained. They are then transformed into a system of nonlinear ordinary differential equations using suitable similarity transformation variables. The resulting nonlinear ordinary differential equations are then transformed to a system of first-order ordinary differential equations and the numerical solution is executed using the collocation method. The effects of the magnetic field, angle of inclination, radiation, Prandtl number, and the exponential stretching of the sheet on the velocity and temperature of the fluid are discussed. It is observed that velocity increases as the sheet is stretched and decreases as the magnetic field and angle of inclination of the magnetic field increases. Temperature increases as magnetic field, angle of inclination, and radiation increase and lowers as the stretching and stratification parameter of the sheet and Prandtl number increases. The findings of this study are in agreement with other previously related work done.

Withdrawn: 2-D numerical simulation of electron MHD acceleration under low magnetic Reynolds number

Abstract The authors made a decision to withdraw the paper.

Magneto-Bioconvection Flow of Williamson Nanofluid over an Inclined Plate with Gyrotactic Microorganisms and Entropy Generation

The fluid flow through inclined plates has several applications in magneto-aerodynamics, materials processing and magnetohydrodynamic propulsion thermo-fluid dynamics. Inspired by these applications, the rate of entropy production in a bio-convective flow of a magnetohydrodynamic Williamson nanoliquid over an inclined convectively heated stretchy plate with the influence of thermal radiation, porous materials and chemical reaction has been deliberated in this paper. The presence of microorganisms aids in stabilizing the suspended nanoparticles through a bioconvection process. Also, the thermal radiation assumed an optically thick limit approximation. With the help of similarity transformations, the coupled partial differential equations are converted to nonlinear ordinary differential equations and the resulting model is numerically tackled using the shooting method. The influences of the determining thermo-physical parameters on the flow field are incorporated and extensively discussed. The major relevant outcomes of the present analysis are that the upsurge in values of Schmidt number decays the mass transfer characteristics, but the converse trend is depicted for boost up values of the thermophoresis parameter. Enhancement in bioconvection Peclet and Schmidt numbers deteriorates the microorganism density characteristics. Further, the upsurge in the Williamson parameter declines the Bejan number and irreversibility ratio.

Experimental and Numerical Analysis of Surface Magneto-Hydrodynamic Propulsion Induced by NdFeB Magnets

Experimental and Numerical Analysis of Surface Magneto-Hydrodynamic Propulsion Induced by NdFeB Magnets

Heat and mass transfer effect on an unsteady MHD radiative chemically reactive Casson fluid over a stretching sheet in porous medium

AbstractThe objective of the present study is to investigate the effects of the variable magnetic field, chemical reaction, thermal radiation, Soret effect, and variable heat absorption on the fluid flow and heat and mass transfer of an unsteady Casson fluid past a stretching surface in a saturated porous medium. Velocity slip near the plate and conjugate heating boundary conditions in heat and mass transfer have been considered in this study. Due to the complexities in boundary conditions, the analytic solution of the governing equations of the present model is not possible. Thus, to overcome these issues, the coupled partial differential equations of the model are converted into a set of ordinary differential equations using similarity transformation. These equations have then been solved numerically using the fourth‐order Runge‐Kutta technique via the shooting method. The effects of various pertinent flow parameters on the velocity, concentration, and temperature field have been studied graphically. For the field of engineering, to get an insight into the physical quantities, especially Nusselt number, Sherwood number, and skin friction, their numerical values have been estimated against various parameters and presented in tables. From the tabulated values, it has been perceived that the shear stress increases with an increase in magnetic parameter, unsteadiness parameter, Casson parameter, and heat source parameter, whereas the Biot number shows the reverse trend. The mixture of porous media has justified that the heat transport process over a stretching sheet results in averting heat loss and accelerating the process of cooling, which is a significant outcome of the study. Furthermore, it has also been revealed that with the increase in the Soret effect and magnetic field, there is a reduction in the fluid velocity and temperature near the plate, whereas there is an increase in the species concentration. It has also been mentioned that the effects of the variable magnetic field have been widely applied in various engineering applications like magnetohydrodynamic (MHD) propulsion forces, rate of cooling, MHD power generation, and so on.

Effect of magnetic field configuration on Faraday MHD accelerator

This works aims at the study of a Faraday electric accelerator with the plasma of argon used as the working gas, which is pre-ionized by nuclear energy. The electron density of plasma is above 1020/m3. Different configurations of magnetic field are numerical studied to obtain the influences on the plasma ionization and flowing characteristics. A relatively higher velocity and electron number density are obtained in monotonically decreasing magnetic field generated by magnet with a shorter length. When the plasma flows through the magnetic field generated by 75-mm magnets, the outflow velocity is 2040 m/s, which is higher than 2016 m/s when the plasma flows through the magnetic field generated by 100-mm magnets.

Electromagnetic Environment Analysis of MHD Propulsion by Surfaces in Sea Water

Magnetohydrodynamic (MHD) propulsion by surfaces is performed through electromagnetic propulsion units mounted on navigations surface in conductive flow fluid (such as seawater or plasma), by which Lorentz force will be generated to propel the near-wall seawater and the navigation. Lorentz force has been used to adjust the flow boundary layer around the cylinder and airfoil. In this study, based on the basic governing equations of fluid dynamics and electromagnetic field, by utilizing finite volume methods, the distribution characteristics of electric and magnetic fields near the propulsion units have been investigated in seawater environment. The results show that the electric and magnetic fields over the surface of the propulsion units rapidly decrease with the normal wall distance. This method can offer a better electromagnetic security.

The operating mode of the water-cooled MHD accelerator of SMGDU with a magnetic field that changed along the channel

The work is aimed at solving the problem of creating in laboratory conditions hypersonic high-enthalpy gas flows that parameters are kept constant for 5-10 seconds. For this purpose the test section of the MHD channel with water-cooled electrodes and side walls was under investigation at the set up with a magnetohydrodynamic accelerator in TsAGI. A new series of runs was performed in which the MHD-acceleration stage was successively increased to 5 seconds. It was determined that the electrical and gas-dynamic characteristics of the MHD accelerator did not depend on the duration of the run. It was first demonstrated that the use of a magnetic field special shaped along the axis of the channel made it possible to avoid catastrophic damage to the side walls of the channel at the entrance and exit of the MHD accelerator, which increased the service life of the installation.

Numerical Study of Operation Mode Effects on Thrust-to-Power Ratio in Diagonal MHD Accelerator

Numerical Study of Operation Mode Effects on Thrust-to-Power Ratio in Diagonal MHD Accelerator

MHD Thruster with Capillary-Porous Electrodes

Capillary-porous electrodes for plasma MHD devices are considered. The electrodes can be continuously renewable and allow one to use a scheme of the inverted MHD generator (i.e., MHD accelerator) as a thruster for interorbital flights. Two types of plasma acceleration are considered: (i) Lorentz force acceleration with a primary current perpendicular to the acceleration direction (Faraday scheme) and (ii) acceleration based on the Hall effect. In the first case, the thruster has advantages only at thrust powers exceeding 1 MW, while in the second case, the thrust and specific impulse are comparable with those of the known analogs (or even surpass them) already at powers of 500–1000 kW. The operating conditions of capillary-porous electrodes are formulated.

Flow characteristics in the water-cooled channel of the MHD accelerator

Many problems related with the development of a hypersonic vehicle and development of new thermal protection materials are directly related to the possibility of conducting a wide range of laboratory researches under conditions that are close to the real flight conditions as possible. In this connection, the work on the formation of high-enthalpy and high-speed gas flows in ground-based installations is of special importance. It is shown in this paper that the flow characteristics required can be achieved using the experimental setup with a magnetohydrodynamic accelerator after its updating. The feature of this research facility is that more than half of the electric energy supplied from electric circuit is converted directly into the kinetic energy of the flow. Preliminary analytical and experimental studies of the MHD accelerator with a water-cooled channel allow one to conclude that a hypersonic flow with duration up to 10 s is formed at the SMGDU path. The total enthalpy in the core of the flow is close to 20 MJ/kg, while a required high level of total pressure is being maintained. The facility with such flow parameters becomes unique and allows one to significantly expand the range of ground-based testing, for example, testing of thermal protection systems, and testing of novel contactless flow control methods for hypersonic flight conditions.

Measurement of heat flux to model surface in the wind tunnel SMGDU

The results of studies of heat fluxes that can occur in the gas supersonic flow created in the wind tunnel with a magnetogasdynamic accelerator are presented. For two operation modes of the installation, measurements of heat fluxes to the surface of a calorimetric model were performed. The dependences of these parameters on induction of magnetic field on axis of the MHD accelerator were obtained for the first time. It was found that their values reached a level of 6 MW/m2. The experimental data were compared with the results of a numerical simulation of a longitudinal flow past cylinder with a flat face in the real conditions of the wind tunnel, that allowed to calculate other characteristics of the gas flow. As a result, it is shown that this setup is enabled to create high-speed gas flows with high enthalpy that can be used in the development of prospective hypersonic aircrafts.