High-pressure Gas Research Articles

Study on influencing factors and prevention measures of coal-rock-gas compound dynamic disaster in deep coal mine mining

Because coal seam mining with high geostress and high gas pressure is prone to coal–rock–gas compound dynamic disasters, a disaster energy equation considering the influence of roof elastic energy is established, and a disaster energy criterion considering the influence of roof elastic energy is derived and introduced into COMSOL software to conduct numerical simulations of coal seam mining under different geostress and gas pressures. The study revealed that the increase of ground stress reduces the gas pressure required for disaster occurrence. When the gas pressure reaches a certain value, the disaster will occur even if the ground stress is very small. When the ground stress and gas pressure are very low, by changing the magnitude of ground stress or gas pressure, outburst, rockburst and coal‒rock‒gas composite dynamic disasters can transform into each other. As the depth of the excavated coal seam increases, the geostress‒gas pressure increases from 15‒0.5 MPa to 20‒0.74 MPa and 25‒1 MPa, the peak stress and peak gas pressure can reach maximum values of 39.61 MPa and 1.11 MPa, respectively, the difference between the elastic energy of the coal rock body and the expansion energy of the gas is not large, and the energy criterion is greater than 1 and increasing, which indicates that the occurrence of a compound dynamic disaster and the degree of hazard gradually increase. The high-pressure water jet slit technology can increase the average gas extraction volume by 3.6 times, the peak stress is transferred from 7 m away from the coal wall to 10 m, and the peak stress is transferred to the deep coal wall, which can effectively reduce the stress in the coal rock mass and the gas pressure in the coal seam.

Studies on Thermal Separation and the Effects of Geometrical and Operating Parameters on the Performance of Pressure Wave Refrigerators

Abstract Thermal separation in a pressure wave refrigerator (PWR) occurs primarily through the propagation of shock waves and reverse-moving rarefied waves produced by injecting a high-pressure gas into a low-pressure residual gas in a receiving tube or channel. The major advantages of PWRs are simple design, low cost, high reliability, low rotational speed, and efficiency comparable to the conventional turbo-expanders. The objectives of this work are to understand the thermal separation in PWRs and to study the effects of various geometrical and operating parameters on the performance of PWRs. Two-dimensional computational fluid dynamics (CFD) simulation using a finite volume method is adopted for this study. The results indicate that the temperature and pressure profiles of the fluid inside the receiving tube just before the discharge, in the region about half the tube length from the inlet nozzle, strongly govern the performance of a PWR. The operating frequency at which the isentropic efficiency attains the first peak value is determined in a generalized way. Within the chosen geometrical and operating parameters, the optimized tube length, operating frequency, and pressure ratio are 2 m, 50 Hz, and 2.5, respectively. The findings in this article will be useful in designing and operating PWRs optimally.

High-Pressure Refrigerant Gas Injection Injury to the Hand

High-pressure injection injuries, although rare, are commonly discussed orthopaedic surgical emergencies. In many cases, high-pressure injection injuries can have detrimental effects on the patient. However, there are rare instances where surgical intervention may be more harmful than helpful. Here, we present a case report of a patient who sustained a high-pressure chemical refrigerant injection injury into the palm of his hand working on an air conditioning refrigeration unit. He was treated nonsurgically with excellent outcomes. The aim of this case report was to bring awareness to the potential nonsurgical management of high-pressure injection injuries in select circumstances.

A controllable and high-pressure gas driven microfluidic platform towards large-scale fabrication of multicolor-emissive carbon dots

A controllable and high-pressure gas driven microfluidic platform is developed for large-scale fabrication of multicolor-emissive carbon dots (CDs).

Upgrading VSL’s high-pressure gas flow primary standard for gases of the energy transition

Upgrading VSL’s high-pressure gas flow primary standard for gases of the energy transition

Impact of trailing-edge modification in stator vanes on heat transfer and the performance of gas turbine: a computational study

Despite extensive studies on the modification of airfoil profiles, most studies have primarily focused on the turbulent wave development and aerodynamic characteristics of modified airfoils. Moreover, studies considering the combined effects of hot-streak conditions at the turbine inlet and the modified profile of stator vanes on gas turbine performance are scarce. Thus, this study conducted a detailed numerical analysis to examine the effects of various trailing-edge (TE) profile modifications at the first stator vane on the heat transfer characteristics and performance of a high-pressure gas turbine. Four cases were investigated: a typical TE (without modification) as the reference case and three modification cases based on the wavelength number (TE-2, TE-4, and TE-8). The Reynolds-averaged Navier – Stokes equations coupled with the k − ω SST γ θ model were employed to solve the complex fluid flow through the 1.5-stage GE-E3 gas-turbine model. The modified cases noticeably increased the heat transfer and aerodynamic characteristics of the blade/vane surface by a maximum of approximately 1–2% owing to the effects of the TE profile on the generation of the passage vortex and secondary flow. This increased the thermal and mechanical stresses, particularly in the hub and shroud regions, which may reduce the fatigue life of the blade/vane components. Furthermore, under the effects of the first stator TE profile on the tip leakage flow, the TE-2 case exhibited a slight increase in the overall efficiency (approximately 0.15%). In contrast, the efficiencies of the other modifications decreased compared to the reference case.

Influence of available impact energy of the testing machine on drop weight tear test characteristics of high toughness pipeline steels

Abstract. Problem. Currently, the problem he methodological issues related to drop load testing (DLT) of rolled plates and pipes made of highviscosity steel for high-pressure gas mains are considered. The imperfection of the current standards in terms of selecting the values of the stored energy of the copra, ensuring the correct testing of metal of the entire size range, is note. Goal Evaluation of the influence of stored copra energy on the results of WIP in terms of the amount of viscous component and absorbed fracture energy of full-thickness specimens of high-viscosity pipe steels widely used in the construction of high-pressure gas pipelines. Methodology. We examined sheets and base metal of pipes of strength classes X65, X70 and X80 of various thicknesses manufactured using thermomechanical rolling technology. The falling load tests were performed on Zwick copters of different capacities. Results The limits of application of the recommendations of APIRP5L3 and EN10274 standards for the choice of the value of the stored energy of the copra during the falling load test of high-viscosity pipe steels have been clarified. The recommendations are applicable only for steels with a thickness of less than 25 mm. Recommendations for selecting the optimal values of the stored energy of the copra at the HDM of high-viscosity pipe steels with a thickness of 25 mm and more are given Originality. The influence of stored copra energy on the results of WIP of high-viscosity pipe steels is estimated. Practical value. Recommendations were issued on the choice of the value of the stored energy of the ERW copra during testing, which will increase the measurement accuracy and reliability of the assessment of the resistance to destruction of gas pipelines

Enhancement of harmonic generation by an intense driving laser with high-order waveguide modes in a high-pressure gas-filled hollow waveguide

High-order harmonics have been widely used as reliable tabletop coherent radiation sources recently, but their applications have often been limited by the available pulse energy. Here, we report that by using an overdriven intense laser in a long waveguide with high-pressure gas, phase matching can be achieved in three distinct “regimes”. In the third regime, favorable phase matching is achieved at near-axis positions to enhance harmonic yields. Our results are supported by a full theoretical analysis, and we demonstrate that coupling of the driving laser with the high-order waveguide modes (instead of the fundamental mode used in most prior experiments) is responsible for achieving phase matching. Furthermore, we establish that this phase matching (and harmonic enhancement) is robust, and a scaling relation is derived for the necessary waveguide and gas parameters, allowing our predictions to be tested immediately in any laboratory today.

A Pressure-Bearing Microwave Transmission Line for Rapid Energy-Efficient Manufacturing Systems of High-End Composite Parts

Currently, a 2-port microwave transmission line with a glass window is usually used to transmit microwave energy to a pressure vessel while sealing the high-pressure gas. In this situation, the damage of the brittle glass window will inevitably result in disastrous accidents. In this paper, the idea of a “2+4”-port microwave transmission line is first proposed to solve this problem. A 4-port waveguide bridge structure is connected to the input port of a traditional 2-port structure, which can release the high-pressure gas safely when the glass window of the 2-port microwave transmitting structure fails. To test this idea, a “2+4”-port microwave transmission line at 2.45 GHz was designed and fabricated. The effectiveness of the whole system in microwave transmission was validated by both simulations and experiments. A high microwave transmittance of more than 97% in the simulation and 91% in the experiment was achieved. The long-time transmission of 15-kW microwave energy, 5 times higher than the previous work, was realized. Moreover, the effectiveness of the transmission line in releasing high-pressure gas (0.6 MPa) was validated by a series of fluid-structure interaction simulations. This research proposes a new transmission structure for transmitting microwave into a pressurized environment safely and efficiently, which can be promoted to a series of applications including vacuum electron devices, microwave ovens, and so on.

An Interpretation Method of Gas–Water Two-Phase Production Profile in High-Temperature and High-Pressure Vertical Wells Based on Drift-Flux Model

With the increasing demand for oil and gas, the depth of some vertical gas wells can reach 6000 m. At this time, the downhole fluid is in a state of high temperature and pressure, and interpretation of the production logging output profile faces the problem of inaccurate production calculations and difficulty judging the water-producing layer. The drift-flux model is usually used to calculate the gas–water two-phase flow. The drift-flux model is widely used to describe the two-phase flow in pipelines and wells because of its accuracy and simplicity. The constitutive correlations used in drift-flux models, which specify the relative motion between phases, have been extensively studied. However, most of the correlations are only extended by laboratory data of small pipe diameters at standard temperature and pressure and do not apply to high-temperature and high-pressure large-diameter gas wells. Therefore, we improved the distribution coefficient and drift velocity of drift-flux correlations in this study for high-temperature and high-pressure gas wells with large pipe diameters. Therefore, this study improved the distribution coefficient and drift velocity of the drift-flux correlations for high-temperature and high-pressure gas wells with large pipe diameters. In practical application, the coincidence rates of gas production and water production calculated by the new drift-flux model were 12.68% and 19.39%, respectively. For high-temperature and high-pressure deep wells, the measurement errors of production logging instruments are significant, and surface laboratory pipelines are challenging to configure and equip with actual high-temperature and high-pressure conditions. Therefore, this study used the method of numerical simulation to study the flow characteristics of the two phases of high-temperature and high-pressure gas and water to provide a basis for identifying the water layer. Combined with the proposed drift-flux correlations and the new method of determining the water-producing layer, a new method of production profile interpretation of high-temperature and high-pressure gas wells is obtained.

Strategi Pemberdayaan Petenak melalui Program Pemanfaatan Biogas dalam Mewujudkan Desa Mandiri Energi di Kecamatan Musuk Kabupaten Boyolali

ABSTRACT The research aims to identify strategies for empowering farmers through biogas utilization programs in realizing Energy Independent Villages. This research was carried out in Sruni Village, Musuk District, Boyolali Regency, in March-April 2024. The method is a survey, the data collection technique in this study uses the Participatory Rural Appraisal (PRA) technique. Data from this study was collected through observation, interviews, and Focus Group Discussions (FGD). The sampling of this study was determined by a census of 45 people. The research data obtained was analyzed using SWOT analysis. The strength factors in this development program are the economic value of biogas is higher than other fuels, the value of biogas benefits is higher, the role of biogas in the value of environmental pollution The role of the government in the development of biogas. The weak factors in this business are the installation of biogas pipes that are easily clogged, and the maintenance of livestock is part-time. The opportunity factor of this program is to become a place of education and encourage the progress of the livestock sector. Threat factors such as perishable biogas installations and high gas pressure temperatures can cause explosions. The empowerment strategy of livestock farmer groups in Sruni Village, Musuk District, Boyolali Regency includes efforts to develop the creative economy, efforts to improve the quality of biogas, efforts to develop biogas installation technology, efforts to strengthen farmer members with groups, efforts to improve livestock business management, efforts to rehabilitate biogas as alternative energy. Keywords: biogas, energy independent villages, focus group discussion (FGD), participatory rural appraisal (PRA), empowerment strategy.

High-Pressure Gas Adsorption on Covalent Organic Framework CTF-1

Triazine-based covalent organic framework CTF-1 was synthesized via polymerization of 1,4-dicyanobenzene in the presence of zinc chloride. Two different methods of the post-synthesis treatment of the obtained material were compared. It was demonstrated that ultrasonication effectively removes impurities from CTF-1. Adsorption of hydrocarbon gases (methane and ethane) and carbon dioxide was measured at 298 K in a wide pressure range for the first time. Ideal selectivity and IAST values for methane/ethane and methane/CO2 pairs were calculated from the obtained isotherms.

NUMERICAL SIMULATION OF THE BEHAVIOR OF NEGATIVE IONS IN A HIGH-FREQUENCY CAPACITIVE DISCHARGE IN CARBON DIOXIDE

In the present work, the dynamics of axial profiles of negative ions and the degree of electronegativity a = Nn / Ne of different parts of the RF capacitive discharge in carbon dioxide are investigated using the SIGLO-rf fluid code. Time-averaged axial profiles of densities of electrons Ne, positive Np and negative Nn ions are also obtained in a wide range of gas pressures and applied RF voltages. It is shown that at a sufficiently high gas pressure (1 Torr and higher), the quasi-neutral plasma consists predominantly of positive and negative ions. The degree of electroneutrality a is about several tens and decreases with increasing RF voltage. Because of oscillations in the RF electric field, electrons are ejected every half-period from a near-electrode sheath to the sheath near the opposite electrode being the temporary anode. This leads to a significant increase in the degree of electronegativity in the sheath abandoned by the electrons. At low carbon dioxide pressures (below 0.17 Torr), the plasma consists predominantly of electrons and positive ions with a very low negative ion density, and the degree of electronegativity is significantly less than unity.

Integration and Design of Cryogenic Hydrogen Fuel Systems for Sustainable Commercial Aviation

The transition to hydrogen-powered aircraft offers an opportunity to significantly reduce carbon emissions in commercial aviation. The use of renewable hydrogen in commercial aviation has the potential to significantly reduce the carbon footprint of the industry. Aviation currently accounts for around 3% of global carbon emissions, a figure that is projected to grow without the adoption of sustainable fuels like hydrogen [1]. Hydrogen can be stored as a compressed gas at high pressure and as a liquid at cryogenic temperatures. However, the unique properties of hydrogen, particularly its low density and cryogenic storage requirements need a complete redesign of aircraft fuel systems. The low density of hydrogen necessitates larger storage volumes compared to conventional fuels, and cryogenic storage requires maintaining extremely low temperatures to prevent boil-off, which can lead to significant fuel loss [2]. This research aims to develop innovative fuel system designs that can efficiently store and deliver cryogenic liquid hydrogen. Numerous tank designs including cylindrical, spherical, and double-walled configurations will be explored. Cylindrical tanks are commonly used for high-pressure gas storage and must be designed to withstand pressure loads effectively. Spherical tanks offer a lower surface area-to-volume ratio, which is advantageous for reducing heat transfer and boil-off. Double-walled configurations provide additional insulation and structural integrity, essential for maintaining cryogenic temperatures [3]. Additionally, effective heat management is crucial in hydrogen fuel systems. The research will explore strategies to recover waste heat from fuel cells or combustion processes, which can be utilized to improve overall system efficiency. This is particularly important in preventing excessive boil-off in cryogenic tanks, which can lead to increased pressure and potential safety issues. By conceiving aircraft designs optimized for either direct liquid hydrogen combustion or fuel cell propulsion, this research aims to create sustainable aviation solutions. Furthermore, this study will develop a detailed thermodynamic model to simulate the behaviour of cryogenic hydrogen fuel systems under various operating conditions, including heat transfer, phase changes and boil-off effects. The goal is to optimize the design and operation of hydrogen fuel systems to achieve maximum efficiency and safety. The findings from this research aim to provide a comprehensive framework for the future of hydrogen-powered commercial aviation. By addressing the unique challenges of hydrogen storage and fuel system design, the study seeks to contribute to the development of sustainable aviation solutions that can significantly reduce the carbon footprint of the airline industry.

Fluorescence imaging of individual ions and molecules in pressurized noble gases for barium tagging in 136Xe

The imaging of individual Ba2+ ions in high pressure xenon gas is one possible way to attain background-free sensitivity to neutrinoless double beta decay and hence establish the Majorana nature of the neutrino. In this paper we demonstrate selective single Ba2+ ion imaging inside a high-pressure xenon gas environment. Ba2+ ions chelated with molecular chemosensors are resolved at the gas-solid interface using a diffraction-limited imaging system with scan area of 1 × 1 cm2 located inside 10 bar of xenon gas. This form of microscopy represents key ingredient in the development of barium tagging for neutrinoless double beta decay searches in 136Xe. This also provides a new tool for studying the photophysics of fluorescent molecules and chemosensors at the solid-gas interface to enable bottom-up design of catalysts and sensors.

A Study on Lightweight Ti-6Al-4V High-Pressure Gas Cylinder for Rapid Cooling of Airborne Electro-Optical/Infrared Sensor

A Study on Lightweight Ti-6Al-4V High-Pressure Gas Cylinder for Rapid Cooling of Airborne Electro-Optical/Infrared Sensor

Gas storage in low-permeability rocks

Low-permeability, dense sandstone formations are ideal for underground gas storage in compressed air energy storage. To examine the gas permeability of fine sandstone under high pressure, a self-developed triaxial high-pressure gas permeameter was used for experiments under varying confining and axial pressures. The study identified unsteady seepage variations and stress dependence in porous media represented by fine sandstone and developed a gas leakage model. Results indicate that the seepage process includes rapid, slow, and cessation stages. Fine sandstone shows excellent storage capacity, with a daily leakage rate of 0.0463%, below required thresholds. This study guides high-pressure gas permeability theories and modeling.

Crack propagation of CoCrFeNiTi-based multiprincipal element alloys formed by laser powder bed fusion in electrolytic hydrogen and high-pressure hydrogen gas environments

Crack propagation of CoCrFeNiTi-based multiprincipal element alloys formed by laser powder bed fusion in electrolytic hydrogen and high-pressure hydrogen gas environments

Study on the gas pressure impact test of gun propellant and fluid-solid coupling dynamics simulation

Abstract In order to reveal the mechanical response characteristics of high-energy propellant under high pressure gas impact, the gas pressure impact test and fluid-solid coupling dynamics simulation of propellant are carried out. The propellant gas pressure impact test device is established. The propellant gas pressure impact tests are conducted under different quality of depressant and thickness of iron pressure relief fragments. The gas pressure-time curve, gas pressure rise and decreasing rate are obtained. It is found that longitudinal and transverse cracks occur locally in propellant under high pressure impact. In order to reveal that mechanical property change of propellant under gas impact, the simulation study on fluid-solid coupling dynamics of gas pressure impact test is carried out using ANSYS Workbench multi-field coupling platform. The flow field pressure in the device and the change process of fixed propellant stress and deformation are obtained. The error of monitoring point simulation and test pressure is 5.3%. The maximum peak value of internal flow field pressure reaches 71.6MPa. The average value of maximum stress and maximum deformation of fixed propellant reaches 220MPa and 1.77mm respectively. It reveals the mechanical response characteristics of propellant under high pressure gas impact.

Yet another structured mesh generator for screw machines simulation

Abstract High-quality structured mesh generation is essential for the numerical simulation and design optimization of screw machines, particularly rotary twin-screw compressors used in high-pressure gas production. Existing meshing techniques often struggle to accurately capture their intricate geometries, limiting their application potential. This paper proposes a novel Isogeometric Analysis (IGA)-based mesh generation approach specifically tailored for twin-screw compressors. Our method leverages high-order B-spline parameterizations derived from boundary representations to enable efficient and precise mesh generation. A novel boundary correspondence technique using Schwarz-Christoffel mapping is introduced to further enhance mesh quality and preserve critical profile features. Additionally, we integrate elliptic grid generation techniques within the IGA framework, combined with a block-diagonal Jacobian-preconditioned Anderson acceleration algorithm, to efficiently solve the associated nonlinear systems. This approach, built upon the open source Geometry + Simulation Modules (G+Smo) library, demonstrates its effectiveness in generating high-quality structured meshes that meet stringent requirements for screw machine simulations, providing a viable alternative for design optimization.