Power Density and Thermochemical Properties of Hydrogen Magnetohydrodynamic (H2MHD) Generators at Different Pressures, Seed Types, Seed Levels, and Oxidizers DOI Creative Commons
Osama A. Marzouk

Hydrogen, Journal Year: 2025, Volume and Issue: 6(2), P. 31 - 31

Published: May 2, 2025

Hydrogen and some of its derivatives (such as e-methanol, e-methane, e-ammonia) are promising energy carriers that have the potential to replace conventional fuels, thereby eliminating their harmful environmental impacts. An innovative use hydrogen a zero-emission fuel is forming weakly ionized plasma by seeding combustion products with small amount an alkali metal vapor (cesium or potassium). This formed can be used working fluid in supersonic open-cycle magnetohydrodynamic (OCMHD) power generators. In these OCMHD generators, direct-current (DC) electricity generated straightforwardly without rotary turbogenerators. current study, we quantitatively qualitatively explore levels electric conductivity resultant volumetric output density typical channel, where thermal equilibrium accelerated at Mach number two (Mach 2) while being subject strong applied magnetic field (applied magnetic-field flux density) five teslas (5 T), temperature 2300 K (2026.85 °C). We varied total pressure pre-ionization seeded gas mixture between 1/16 atm 16 atm. also seed level 0.0625% 16% (pre-ionization mole fraction). type cesium potassium. oxidizer air (oxygen–nitrogen mixture, 21–79% mole) pure oxygen. Our results suggest ideal reach exceptional beyond 1000 MW/m3 (or 1 kW/cm3) provided absolute reduced about 0.1 only for rather than Under atmospheric air–hydrogen (1 pressure) 1% fraction vapor, theoretical 410.828 case 104.486 The enhanced using any following techniques: (1) reducing pressure, (2) instead potassium seeding, (3) oxygen (if unchanged). A 4% fraction) recommended. Much lower much higher may harm performance. maximizes not necessarily same conductivity, this due additional thermochemical changes caused additive seed. For example, combustion, maximized 6% fraction, 5%. present comprehensive set computed properties gases, such molecular weight speed sound.

Language: Английский

Optimizing Hydrogen Storage and Fuel Cell Performance Using Carbon-Based Materials: Insights into Pressure and Surface Area Effects DOI Creative Commons
Ali Altuntepe, Selahattin Çelik, Recep Zan

et al.

Hydrogen, Journal Year: 2025, Volume and Issue: 6(2), P. 22 - 22

Published: March 30, 2025

Efficient hydrogen storage is critical for advancing hydrogen-based technologies. This study investigates the effects of pressure and surface area on in three carbon-based materials: graphite, graphene oxide, reduced oxide. Hydrogen adsorption–desorption experiments under pressures ranging from 1 to 9 bar revealed nonlinear capacity responses, with optimal performance at around 5 bar. The specific plays a pivotal role, oxide exhibiting 70.31 m2/g, outperforming (33.75 m2/g) graphite (7.27 m2/g). Reduced achieved highest capacity, 768 sccm 3 wt.% increase over other materials. In assessing proton-exchange fuel cell performance, this found that increased correlates enhanced power density, reaching maximum 0.082 W/cm2, compared 0.071 W/cm2 0.017 However, desorption rates impose temporal constraints operation. These findings enhance our understanding pressure–surface interactions underscore balance between area, practical materials, offering valuable insights applications.

Language: Английский

Citations

0
Power Density and Thermochemical Properties of Hydrogen Magnetohydrodynamic (H2MHD) Generators at Different Pressures, Seed Types, Seed Levels, and Oxidizers DOI Creative Commons
Osama A. Marzouk

Hydrogen, Journal Year: 2025, Volume and Issue: 6(2), P. 31 - 31

Published: May 2, 2025

Hydrogen and some of its derivatives (such as e-methanol, e-methane, e-ammonia) are promising energy carriers that have the potential to replace conventional fuels, thereby eliminating their harmful environmental impacts. An innovative use hydrogen a zero-emission fuel is forming weakly ionized plasma by seeding combustion products with small amount an alkali metal vapor (cesium or potassium). This formed can be used working fluid in supersonic open-cycle magnetohydrodynamic (OCMHD) power generators. In these OCMHD generators, direct-current (DC) electricity generated straightforwardly without rotary turbogenerators. current study, we quantitatively qualitatively explore levels electric conductivity resultant volumetric output density typical channel, where thermal equilibrium accelerated at Mach number two (Mach 2) while being subject strong applied magnetic field (applied magnetic-field flux density) five teslas (5 T), temperature 2300 K (2026.85 °C). We varied total pressure pre-ionization seeded gas mixture between 1/16 atm 16 atm. also seed level 0.0625% 16% (pre-ionization mole fraction). type cesium potassium. oxidizer air (oxygen–nitrogen mixture, 21–79% mole) pure oxygen. Our results suggest ideal reach exceptional beyond 1000 MW/m3 (or 1 kW/cm3) provided absolute reduced about 0.1 only for rather than Under atmospheric air–hydrogen (1 pressure) 1% fraction vapor, theoretical 410.828 case 104.486 The enhanced using any following techniques: (1) reducing pressure, (2) instead potassium seeding, (3) oxygen (if unchanged). A 4% fraction) recommended. Much lower much higher may harm performance. maximizes not necessarily same conductivity, this due additional thermochemical changes caused additive seed. For example, combustion, maximized 6% fraction, 5%. present comprehensive set computed properties gases, such molecular weight speed sound.

Language: Английский

Citations

0