Numerical models for the evaluation of cryo-adsorbent based hydrogen (H 2 ) storage systems for fuel cell vehicles were developed and validated against experimental data. These models simultaneously solve the equations for the adsorbent thermodynamics together with the conservation equations for heat, mass, and momentum. The models also use real gas thermodynamic properties for hydrogen. Model predictions were compared to data for charging and discharging both activated carbon and MOF-5™ systems. Applications of the model include detailed finite element analysis simulations and full vehicle-level system analyses. The full system models were used to compare prospective system design performance given specific options, such as the adsorbent materials, pressure vessel types, internal heat exchangers, and operating conditions. The full vehicle model, which also allows the user to compare adsorbent systems with compressed gas, metal hydride, and chemical hydrogen storage systems, is based on an 80 kW fuel cell with a 20 kW battery evaluated using standard drive cycles. This work is part of the Hydrogen Storage Engineering Center of Excellence (HSECoE), which brings materials development and hydrogen storage technology efforts together to address onboard hydrogen storage in light duty vehicle applications. The HSECoE spans the design space of the vehicle requirements, balance of plant requirements, storage system components, and materials engineering. Theoretical, computational, and experimental efforts are combined to evaluate, design, analyze, and scale potential hydrogen storage systems and their supporting components against the Department of Energy (DOE) 2020 and Ultimate Technical Targets for Hydrogen Storage Systems for Light Duty Vehicles.

Due to its high efficiency, fast cool-down, small size, light weight, low power consumption, high reliability, Stirling cycle machine has many successful commercial applications such as heating and cooling. In the present paper, performances of a Beta type Stirling machine having a regenerative displacer were investigated. Energy analysis is reproduced taking into account complex phenomena related to compressible fluid mechanics, thermodynamics and heat transfer. A special attention is paid to the effect of such operating parameters as pressure, temperature, frequency and cooling water flow rate on Beta type regenerative Stirling machine performances. A MATLAB program was developed. Net cooling capacity, imputed work and COP inside the machine were assumed and compared to the experimental values. Comparing the results obtained by this code with experimental data, an acceptable agreement can be deduced for the predicted performance of the Stirling machine. The optimum speed is investigated.

Cavitation is not only driven by the pressure difference, but also affected by the temperature difference. In high temperature water or cryogenic fluids, temperature decline of liquids is caused by latent heat of vaporization. The cavitation characteristics in this conditions are different from that of room temperature. The thermodynamic effects of cavitation have very important application in the fluid machine, so high temperature and low temperature cavitation are comprehensively applied at the astronautics. The presented paper researched thermodynamics cavitation based on the Rayleigh-Plesset equation and deduced a new thermodynamics cavitation model with fully considering thermodynamic effects on the basic transport equation. The airfoil NACA0015 was calculated by the new model and the thermal cavitation characteristic was calculated at different temperature, that is, 25°C, 50°C and 100°C. Besides, the pressure coefficient was contrasted with experiment data at different temperature. The centrifugal pump’s suction performance curve was calculated at 25°C and 100°C respectively, and the main conclusion is that the suction performance of the pump at the high temperature is better than that at the normal temperature. The thermodynamic effects of cavitation model are more accurate at predicated centrifugal pump’s suction performance, which can provide beneficial referenced indicator for energy conservation.

Low solubility compounds suffer from lack of data, leading to an impoverishment in thermodynamic parameters such as Gibbs free energy (ΔG), enthalpy of dissolution (ΔH), entropy (ΔS), infinite dilution coefficient (γ ∞ ) and isobaric heat capacity (C p ) of utmost practical importance for industrial optimization processes. Dynamic fluid method is a novel technique for low solubility (expressed as molar fraction χ) determination based on the saturation of a specific heated fluid passing through a saturation cell. The heated components are kept inside a chromatographic oven maintained at a constant temperature to within ± 0.05°C by means of a PID temperature controller. A regular stream of fluid, using a constant flow pump, passes through the saturation cell packed with an inert stationary phase (Gaz chrom R 60/80) pre-coated with the organic compound. The solute transported by the fluid is subsequently trapped in a specific extraction column (inverse phase). The organic compound is removed by back flushing using the appropriate solvent in order to dissolve and carry out the totality. A low flow of fluid through the generator column is to be set to avoid safely the formation of colloidal dispersion, to increase the contact time and to keep small pressure drops across the generator/extractor column. The gas chromatography coupled to mass spectrometer detector is used in order to quantify the solute. The validation of this apparatus was achieved by comparison of our values with the ones extracted from previous papers using the static method to determine aqueous solubility of the ethylbenzene, and a precision of our solubility measurements was established to be better than 0.2%. In continuous, aqueous solubility and thermodynamics properties of perfluorocarbons compounds were determined in the range of temperature from 273 K to 333 K. Considering the contribution of chromatographic, calibration and other operational errors, the combined measurement uncertainty (standard deviation) was established to be less than 3%.

In this study, a flat heat pipe is proposed to use the enormous heat capacity of the soil as a heat sink to remove heat from the ambient and a the same time provides a heat pathway for the external irradiation so that the thermal insulation of the construction is significantly improved. Heat pipes offer an effective and attractive alternative since they work with a small temperature budget. Heat pipes use the latent heat of vaporization as a heat transfer mechanism and provide a very high effective conductivity. Heat pipes are not thermodynamics cycles then do not suffer from the Carnot limitation. Temperature drop in the vapor core is very small and the vapor provides an almost isothermal condition. The operational temperature of a heat pipe is controlled by the conditions in the condenser (in this case, the soil). So, providing an effective heat transfer pathway in the condenser, the vapor temperature will be closed to the temperature of the soil. Soil temperature does not fluctuate bellow certain distance from the surface and in a tropical climate is always cooler that the ambient and can function as a heat sink. As part of this research, a full transient analysis of the operation of a flat heat pipe is carried out. With the insight of numerical results, a flat heat pipe thermal panel can be constructed and tested to verify the feasibility and actual performance of the flat heat pipe panel.

The need for Out-Of-Position (OOP) simulation capabilities in crash safety software has risen in importance in the automotive industry after the final ruling of FMVSS 208 by the National Highway Transportation Safety Administration (NHTSA) in 2000. However, because of current technical challenges, the thermodynamics airbag models are not capable of either accurately simulating the flow-bag interactions under OOP conditions, or differentiating the effect of some important design changes, such as vent locations, inflator configuration, and flow diverging devices. The development of these capabilities entails overcoming tremendous technical challenges and numerical difficulties in computational fluid dynamics (CFD) and crash simulations due to the complexity and extreme conditions of OOP. This paper summarizes the developments of algorithms used in the context of an Arbitrary Lagrangian-Eulerian (ALE) formulation. The main developments of this study include the gas dynamic model for mixing gases, the special treatment of inflator gas flows, a penalty based fluid-structure coupling algorithm, and a permeability algorithm for porous fabrics. To expedite the developments and resolve the technical difficulties, a set of benchmark problems was used in this study. Each of the benchmark problems addresses specific technical difficulties of airbag OOP simulations by comparing simulation results to analytical solutions, well-known numerical solutions, or test results. The benchmark set was designed to start from simple CFD problems and progress to the most complicated OOP applications such that the weakness and algorithmic errors of the simulation code can be easily identified. Simulation results of the benchmark problems and the issues addressed by them are discussed in this paper. The simulation results have demonstrated that LS-DYNA now has the capabilities to simulate certain OOP problems.

The paper deals with a 3-D numerical simulation and validation against industrial measurements of turbulent frozen reacting flow in a subsonic compressible gas Venturi’s ejector used as “fluid dynamic engine” for external flue gas recirculation in a state-of-the-art “annular shaft” lime kiln. Higher stagnation thermodynamics parameters of the ejector hot gas primary stream permit the avoidance of the condensing temperature window of compounds such as K 2 O and Na 2 O, and KCl and NaCl that produce sticky builds-up on the ejector’s internal wall. An improved gas dynamics effectiveness allows the maximization of the amount of secondary flue gas stream using much less primary stream mass flow rate. The commercial Fluent™ UNS/5 software was used to predict all flow behavior characteristics inside the original and new Venturi’s ejectors. A reasonable agreement has been found between the computed and experimental flow rate figures of the secondary flue gas stream of the actual functioning kiln.

A review of status is presented, discussing hydraulic power recovery of fluid streams expanding with or without gas evolution. Point of departure for the treatise given, is embedded in basic thermodynamics and fluid mechanics. Formulae for estimating isentropic power recovery are derived, which hold asymptotically for low gas to liquid mass fraction. These formulae provide simple means for calculating power recovery with gas evolution, given a certain vapor void fraction. The key element in the entire approach is to attribute the extra power recovery due to gas evolution to the change in density of the fluid stream. The formulae and discussions presented in the paper may assist the (application) engineer in evaluating the effect of vapor evolution with regard to hydraulic performance of hydraulic power recovery turbines. The paper further also discusses the condition of (runaway) overspeed, as this should not be omitted from a review on basic considerations for hydraulic power recovery turbines. Formulae and calculation methods are given for calculating runaway speed, choke flow and time to runaway speed.