The "SpaceTRIPS" facility is a novel energy conversion technology that uses thermoacoustic phenomena coupled with liquid metal magnetohydrodynamic techniques. This technology can be used for electricity power generation in long-term deep Space missions, as well as in the energy sector for terrestrial applications. The thermoacoustic engine is supplied with heat, and this thermal power is converted to sound in the form of mechanical vibrations. This sound is further converted to electrical power by using liquid metal oscillations in magnetic field, created by permanent magnets. The prototype of this technology is constructed at the Institute of Physics, University of Latvia. Thermoacoustic excitation is created due to the heat introduced by radioisotopes. The Americium is considered to be a reasonable option for this due to its high half-life period, which could provide heat resulting from nuclear reactions for several decades-long missions. At the same time, thermoacoustic technology also allows the utilization of other heat sources, such as residual waste heat from industrial processes, as well as solar heat from the sun, for terrestrial applications. The main drawback of this technology is the existence of the liquid metal-free surface, which, during vertical vibrations, tends to become unstable, resulting in so-called Faraday surface waves. It is possible to suppress this instability by using electromagnetic stabilization with an external magnetic field. To prove this hypothesis, a modeling mockup was built that consists of two loudspeakers that are positioned opposite to each other and connected in push-pull mode, thus simulating the performance of the thermoacoustic engine. This mockup was used as a test bench to perform experiments by testing various free surface stabilization aspects and techniques. The results will be described in the present work.

This study presents a carbon footprint assessment of a novel electroslag method for cadmium (Cd) recovery from spent nickel–cadmium (Ni-Cd) batteries in comparison with the carbon footprints of pyrometallurgical and hydrometallurgical cadmium recovery methods. A comparison of CO2 emissions in three types of technological processes during the recovery of 1 kg of cadmium is carried out. Energy inputs and CO2 emissions are calculated for the electroslag process and compared to conventional methods, such as pyrometallurgical and hydrometallurgical reduction methods. The electroslag process eliminates cadmium vaporization by using molten KCl–NaCl flux and carbon under electromagnetic stirring. Cadmium reduction occurs under a layer of flux, which prevents the contact of the reduced cadmium with the atmosphere. The electroslag process temperature is limited to 700 °C, which is lower than the boiling point of cadmium (767 °C). The electroslag remelting process uses molten KCl–NaCl flux and carbon as a reductant under electrovortex flow stirring. The pyrometallurgical method for extracting cadmium from nickel–cadmium batteries is based on the reduction of cadmium with carbon at high temperatures. In the pyrometallurgical process, coal (anthracite) is used as the carbonaceous material, which can extract 99.92% of cadmium at 900 °C. Cadmium is separated using a vacuum at temperatures ranging from 800 °C to 950 °C for several hours. Hydrometallurgy is a metal extraction process involving chemical reactions that occur in organic or aqueous solutions at low temperatures. The hydrometallurgical process involves a series of acid or alkaline leaches, followed by separation and purification methods such as absorption, cementation, ion exchange, and solvent extraction to separate and concentrate metals from leach solutions.

Magnetohydrodynamic pumps with permanent magnets are a promising technology for metal transportation using the electromagnetic interaction between an electrically conducting fluid and a magnetic field. This paper presents a numerical 3D magnetic field distribution is compared with an experimentally measured magnetic field mapping in the liquid metal channel. With a solid body approximation, this data is further used to calculate the pressure-flowrate characteristics by an electrodynamic approach. Agreement was obtained the measured pressure-flowrate characteristics when testing an electromagnetic pump prototype. The test was conducted in the newly designed sodium loop at the Institute of Physics University of Latvia (IPUL).

In this paper, an electrical generator is presented for the exploitation of alternating energy. Some renewable sources are directly available in such forms, such as the wave power obtainable from the sea, but most of them can be converted to alternative forms; therefore, the proposed generator can be applied to different kinds of renewable sources. In particular, the proposed system is thought to be coupled with a thermoacoustic engine, which converts heat into mechanical vibration without using solid moving parts. This opens the proposed system to the use of most thermal sources, such as solar radiation, waste recovery, geothermic, car exhaust, and others. The object of of this present work concerns the transformation of alternating mechanical energy into electricity by using a specific type of magnetohydrodynamic (MHD) disk generator. The functioning of this generator is based on the interaction between a DC magnetic field embedded in a disk structure and a conducting fluid held in an inner channel. A simplified model of the generator is presented here, and a sensitivity analysis is performed. It is shown that, under specific operating conditions, the efficiency of the system can reach 70% with a level of power of hundreds of watts.

Experimental and numerical research in a strong magnetic field is described in this article testing silicon carbide (SiC) flow channel inserts (FCI) in lead-lithium (PbLi) liquid metal flow. The study aims to further develop the High-Temperature Dual-Coolant Lead-Lithium nuclear fusion blanket concept by testing new variations of SiC inserts operating in the relevant electromagnetic conditions. These inserts act as electrical insulators in magnetohydrodynamic lead-lithium flow and can also play the role of the thermal insulator in the potentially real fusion environment. The liquid metal pressure and integral flowrate measurements were performed on up to 5T DC magnetic field created by a superconducting magnet at high temperatures up to 700 degrees C, which is close to the real fusion environment. Comparisons of several cases with and without inserts are provided, demonstrating their impact on hydraulic resistance. Additionally, electrical potential distribution is recorded on the leadlithium channel walls, which can be used to evaluate the character of liquid metal velocity distribution in the lead-lithium channel.

The electromagnetic pumps on permanent magnets are a promising technology for liquid metal transportation using electromagnetic interaction between electrically conducting fluid and magnetic field. In this article, a numerical 3D magnetic field distribution is provided and compared with experimentally measured magnetic field mapping in the liquid metal channel. Using an electrodynamic approach, this data is further used to calculate the pump pressure-flowrate (p-Q) characteristics in the solid body approximation. A good agreement is obtained with experimentally measured p-Q characteristics during the pump prototype tests. The experiment was conducted on the newly designed liquid sodium (Na) loop at the Institute of Physics of the University of Latvia (IPUL).

This study aimed to investigate the performance of an electromagnetic induction pump with rotating permanent magnets under different inlet pressure conditions. The tested cylindrical-type pump was placed in the test loop to test its parameters while pumping liquid sodium. The measurements of the pump characteristics were carried out at the different inlet pressure values. The inlet pressure was varied, changing initial overpressure in the loop's expansion tank from 0,1 to 1,75 bars. Inlet pressure influenced the cavitation occurrence in the pump channel, and thus, the maximal flow rate varied from 15,2 to 73 l/s. In addition to the pressure-flow rate characteristics, various data were collected during the experiments, such as drive unit power, vibration data, and acoustic signals. Analysis of these parameters showed a clear correlation between the inlet pressure and the apparent cavitation process in the pump channel. This study aimed to establish the operational limits for the electromagnetic induction pump with rotating permanent magnets. The results indicate that the pump can safely operate within the range of inlet pressure values of 0,6 bar and cavitation number values of 3,2.

The research is aimed at investigating the influence of the cavitation process on the performance of the electromagnetic induction pump with rotating permanent magnets operating in the circulation loop, where low pump inlet pressure values are maintained. Data on the inlet pressure influence on pressure-flow rate curves were obtained by an experimental approach using a disc-type pump with SmCo permanent magnets in experiments. The pump was placed in the test loop operating with liquid sodium, and measurements of the pump characteristics were made. The inlet pressure variation from 0.1 to 3.0 bar influences the maximum flow rate, thus varying it from 2 to 12 l/s. Figs 7, Refs 7.

Electricity production is a major problem for deep space exploration. The possibility of using radioisotope elements with a very long life as an energy source was investigated in the framework of an EU project “SpaceTRIPS”. For this, a two-stage system was tested, the first in which thermal energy is converted into mechanical energy by means of a thermoacoustic process, and the second where mechanical energy is converted into electrical energy by means of a magnetohydrodynamic generator (MHD). The aim of the present study is to develop an analytical model of the MHD generator. A one-dimensional model is developed and presented that allows us to evaluate the behavior of the device as regards both electromagnetic and fluid-dynamic aspects, and consequently to determine the characteristic values of efficiency and power.

Latvia in the 11th–13th century poses a curious case for the coexistence of two different practices of Baltic ware production. The Baltic ware pots from lower reaches of the River Daugava and from the Courland region look not just stylistically, but also technologically different. Our paper assessed the production traces by using macro-observations, Reflectance Transformation Imaging (RTI) and extensive ethnographic material of Slavic pottery production of the 1900s, as well as using modern replicas as visual aids to assist in the identification of the principal coil attachment methods. The results showed that potters from the lower reaches of Daugava used the wheel’s rotation extensively during the shaping process of Baltic ware. The production of the pots required the potter to possess a level of technical skill which implied a level of professionalisation. Baltic ware from Courland was less technically complicated and used comparatively more of the methods of handmade pottery production.

Our research is inspired by the Space Thermoacoustic Radio-Isotopic Power System Project SpaceTRIPS [1] for deep space applications: a radio-isotopic source produces heat, a thermoacoustic engine converts it into sound. The MHD generator further converts sound into electricity. The present paper does not refer to the full project, but to an internal process inside the MID) generator. Reasonable parameterization allows analyzing the MIID generator in two steps. At first, we convert our knowledge about the magnetic field and generator geometry into an equivalent circuit with three inductances and two resistances. Afterwards a standard circuit calculation gives all working properties. For decades, the Institute of Physics has been developing conductive MHD generators acting in a DC mode. Now we have to adopt our experience [2] in an AC mode.

Alkaline nickel-cadmium batteries are among the most used industrial high-power sources. Despite stricter environmental requirements, nickel-cadmium batteries still remain as the main choice for highly reliable power sources for heavy-loaded equipment. Therefore, recovery of cadmium (Cd) from spent batteries is a challenge for the modern recycling industry, particularly as it displays high bio-toxicity. The present study describes a new green approach for Cd recovery from cadmium oxide (CdO). The paper discusses using a ternary chloride composition consisting of calcium, potassium and sodium chloride, thereby avoiding the release of Cd vapour from the reaction volume during the reduction reaction from CdO. For the protective slag layer during the reduction process (which occurs at 650 °C), a 0.515:0.0796:0.405 molar ratio of CaCl2:KCl:NaCl was chosen, with the aim of achieving a melting point at 483 °C. To describe phase and elemental composition of obtained products X-ray diffraction analysis and energy dispersive X-ray spectroscopy, respectively, were applied. Electron and optical microscopy were used for morphological observations. The presence of the metallic Cd was noted. During the reduction reaction, it was noted that slag separated into two parts: a protective upper layer and bottom layer. It was also noted that metallic Cd accumulated with increasing reaction time in the bottom part of the slag.

Thermoacoustic-to-MHD energy conversion is a potential key technology for energy production in deep Space, due to the absence of moving mechanical parts or electrical contacts [1]. This technology has been developed by a team of scientists from different institutes and companies from France, Italy, Latvia and Germany. Experimental results of the prototype built at the Institute of Physics, University of Latvia, are presented in this paper. It summarizes the results of several TAc-alone experimental sessions, indicating the required temperature difference and working gas mean pressure. These are the necessary parameters needed for the induction of acoustic power. The paper also discusses the operational experience gained in a preliminary water simulation for the MHD-alone experiment.

This paper discusses the results of theoretical and experimental investigation of magnetohydrodynamic generator with liquid metal working body. This electric machine is used to convert mechanical energy, supplied by thermoacoustic engine, to an AC form of electrical energy. The purpose of this technology is an electricity production in deep Space, potentially suitable for long term missions far away from Sun.

The paper presents experimental results on testing a travelling wave thermoacoustic (TAc) engine using argon gas coupled with a 200 W, low-power, magnetohydrodynamic (MHD) generator using liquid sodium. The project is a terrestrial test and simulation of a radio isotopic-fed electrical power supply system for deep space applications. A large range of parameters were analyzed, such as TAc generated pressure oscillation amplitude as a function of the mean pressure and temperature of the heater.

In this paper are presented a new results of testing travelling wave thermoacoustic (TAc) generator, coupled with alternating current magnetohydrodinamic (MHD) generator in FP7 project „Space Trips”. This project relates to experimental testing of radioisotopic-feeded electrical power supply system for deep space applications. There are analized and described experimental graphs of thermoacoustic generator like pressure oscillation amplitude as a function of mean pressure and temperature. A certain extrapolation of them had been performed. Also a thermoacoustic excitation graph is plotted, where are shown critical values when acoustic power generation starts to generate soundwave.