This study examines the directional hydrodynamic resistance parameters of woven mesh screens under steady-state and oscillating helium flows, relevant for both small-scale and large-scale regenerative cryocoolers. Computational fluid dynamics (CFD) simulations are employed to analyze commercially available mesh screen fillers and determine pressure drops in both axial and lateral (radial)...
Liquid air energy storage (LAES) technology is distinguished by its high energy density, long-cycle energy storage capacity, and geographic independence, presenting substantial potential for large-scale integration of renewable energy and grid management. Current studies on LAES system performance predominantly focus on steady-state models, with an emphasis on improving round-trip efficiency...
Liquid hydrogen has garnered unprecedented attention due to its unique advantages in low-carbon energy economies and the realm of high-thrust and environmentally friendly space propulsion systems. The boiling phase change is a fundamental and inescapable physical process in every aspect of liquid hydrogen storage, transportation, and vaporization applications. Accurate prediction of boiling...
An important aspect to enable widespread adoption of electric aircraft propulsion is to develop lighter and higher-ampacity cables to carry the high current and voltage at the same time. To address this, we developed a power transmission cable for electric aircraft that utilize cryogen-flow cooling to enhance transmission efficiency. The cable uses multi-stranded aluminum wire as the...
Cavitating fluid transients occur when sudden changes in flow, such as rapid acceleration or deceleration, cause significant pressure variations in a pipeline. These variations generate oscillatory pressure waves, leading to the formation and collapse of vapour cavities when the pressure during the rarefaction wave drops below the vapour pressure. During collapse, these cavities can emit...
A three-dimensional numerical simulation method is developed to predict the heat transfer characteristics during the flow boiling of cryogenic slurry in horizontal circular pipes, based on Euler-Euler model with a boiling model for liquid-vapor mass transfer. The model incorporates the Ishii model for vapor-liquid interaction and the Huilin-Gidaspow model for solid-liquid interaction, also...
The efficiency of hydrogen liquefaction and other cryogenic applications is potentially increased by using mixed refrigerants. The cryogenic phase equilibria test stand CryoPHAEQTS at KIT enables the measurement of physical property data of all cryogenic fluid mixtures in a temperature range from 10 K to 300 K and at pressures up to 150 bar.
Neon and helium are essential components of...
A thermal multi-zone model is used to describe the self-pressurization process in a liquid helium storage tank. This model divides the liquid and ullage of the tank into multiple zones taking into account the effects of the boundary layer in each zone. Combined with helium property parameters from REFPROP, the model can calculate the self-pressurization process of a liquid helium storage tank...
