High Pressure Temperature Research Articles

A novel model for the thermoelastic hydrodynamic lubrication characteristics of the slipper pair in radial piston pumps

Relying on heat conduction and thermoelastic mechanics theories and Takeuti's research, a novel TEHL (thermoelastic hydrodynamic lubrication) model considering thermal effect-induced thermoelastic deformation was developed. The impact of the radial piston pump's slipper pair's working and structural parameters on lubrication under heavy oscillating load was studied. The model was shown to be valid and superior in simulating oil film changes in TEHL, EHL (elastic hydrodynamic lubrication), and HL (hydrodynamic lubrication). It was first used to analyze how different conditions and parameters affect slipper pair lubrication. Thermoelastic deformation simulations were more accurate than previous elastic ones, making results more comprehensive. Friction experiments gave a coefficient of about 0.25 at 400–600 r/min and 0.23 at 600–1000 r/min, while the simulation result was 0.215. The HL model had a thin film, high temperature, and asymmetric pressure at x1 during suction, and increased thickness, decreased temperature, and uniform pressure at y1 during high pressure. In the HL model without deformations, the film was 12.9–14.0 μm thick and 345.7–354.0 K in temperature. In the EHL model with elastic deformation (0.6–2.6 μm), the thickness was 13.6–15.9 μm. In the TEHL model with thermoelastic deformation (0.5–2.1 μm), the thickness was 13.2–15.6 μm and the temperature was 344.4–354.0 K. Also, film thickness, speed, pressure, angle, radius, and ratio significantly affect slipper pair TEHL. This series of simulations proved the proposed model's feasibility for studying TEHL under heavy, variable loads and different structures. The model can optimize pump design parameters, boosting efficiency, and extending service life, and also enables fault prediction and prevention and maintenance strategy optimization, enhancing equipment reliability and production efficiency.

High pressure and high temperature synthesis of a new boron carbide phase

The dense boron carbide (B-C) phases with diamond structure are predicted to be superhard, with hardness close to that of a cubic boron nitride (c-BN). At ambient conditions, graphite-like BC3 is well characterized, firstly reported by Kouvetakis et al. In this work, we have synthesized a new B-C phase from the graphite-like BC3 in a laser-heated diamond anvil cell. Interestingly, this phase could be recoverable to ambient pressure due to dynamic stabilities. The Raman spectrum and X-ray diffraction patterns give the possible structure of this new phase.

Microwave synthesis of molybdenum disulfide quantum dots and the application in bilirubin sensing

Molybdenum disulfide quantum dots (MoS2QDs) is a new type of graphite like nanomaterial, which exhibited well chemical stability, unique fluorescence characteristics, and excellent biocompatibility. The conventional hydrothermal synthesis of MoS2generally requires a long-term reaction at high temperature and high pressure. Herein, we have developed a simple and fast MoS2QDs synthesis scheme using microwave heating, and further modified the surface of MoS2QDs using 3-aminophenylboronic acid. The 3- aminophenylboronic acid modified MoS2QDs (B-MoS2QDs) were further coated by a zinc-based metal-organic backbone (ZIF-8) in a solution containing zinc ions and 2-methylimidazolium. The constructed nanohybrid B-MoS2@ZIF-8 were successfully applied to the visualization and rapid detection of bilirubin based on the ratiometric fluorescence changes. The linear range for bilirubin detection is 0.2-75 μmol·l-1, and detection limit is 0.017 μmol·l-1.

Microwave-Assisted Synthesis of Carbon Nanospheres and Their Application as Plugging Agents for Oil-Based Drilling Fluids

Wellbore instability caused by the invasion of drilling fluids into formations remains a significant challenge in the application of oil-based drilling fluids (ODFs). In this study, carbon nanospheres (CNSs) were synthesized using glucose as the carbon source through a microwave-assisted method. The effects of the reaction temperature, carbon source concentration, and reaction time on the particle size of CNSs were systematically investigated. The results revealed that under optimal conditions, CNSs with an average particle size of 670 nm were successfully synthesized, exhibiting high sphericity and excellent dispersibility. CNSs demonstrated stable dispersion in mineral oil when lecithin was used as a dispersant. The plugging performance of CNSs in ODFs was evaluated through low-pressure filtration and high-temperature, high-pressure (HTHP) filtration tests. After aging at 180 °C for 16 h, the addition of 2% CNSs reduced the filtration volume from 10.6 mL to 2.5 mL on standard filter paper (average pore size: 3 μm) and from 8.5 mL to 1.6 mL on microporous membranes (average pore size: 0.5 μm). Additionally, the HTHP filtration volume decreased from 73 mL to 18 mL, and the permeability of the filter cake formed during HTHP filtration was reduced from 26.5 × 10−3 mD to 1.2 × 10−3 mD. Furthermore, CNSs improved the rheological properties and emulsion stability of ODFs. With excellent compatibility and applicability, CNSs offer a promising solution for enhancing the performance of oil-based drilling fluids.

From Powders to Performance-A Comprehensive Study of Two Advanced Cutting Tool Materials Sintered with Pressure Assisted Methods.

This paper presents a comprehensive study of two tool materials designed for the machining of Inconel 718 superalloy, produced through two distinct sintering techniques: High Pressure-High Temperature (HPHT) sintering and Spark Plasma Sintering (SPS). The first composite (marked as BNT), composed of 65 vol% cubic boron nitride (cBN), was sintered from the cBN-TiN-Ti3SiC2 system using the HPHT technique at a pressure of 7.7 GPa. The second composite (marked as AZW) was fabricated from the Al2O3-ZrO2-WC system using SPS at a pressure of 63 MPa. The final phase composition of BNT material differed significantly from the initial composition due to reactions occurred during sintering. In contrast, the phase composition of the AZW ceramic composite before and after sintering was similar. The materials exhibited high quality, as evidenced by a Young's modulus of 580 GPa for BNT and 470 GPa for AZW, along with hardness of 26 GPa for BNT and 21 GPa for AZW. Both composites were used to prepare cutting inserts that were evaluated for their performance in machining Inconel 718 alloy. While both inserts showed durability comparable to their respective reference commercial inserts, they differed in performance and price relative to one another.

Ultrasonic backscattering model of lamellar duplex phase microstructures in polycrystalline materials.

Carbon steel and low alloy steel are pearlitic heat-resistant steels with a lamellar microstructure. There are good mechanical properties and are widely used in crucial components of high-temperature pressure. However, long-term service in high-temperature environments can easily lead to material degradation, including spheroidization, graphitization, and thermal aging. This study proposes a theoretical model of ultrasonic backscattering with a lamellar structure in pearlite areas. It analyzes the effects of different pearlite area ratios and interlamellar spacing on ultrasonic backscattering signals. A Voronoi diagram is used to constructs a two-dimensional finite element (FE) model of the lamellar structure, and the effects of different pearlite area ratio and interlamellar spacing on the backscattering signals are analyzed to verify the correctness of the theoretical model. By preparing spheroidization samples of various grades, the change values of pearlite area ratio and interlamellar spacing are measured. The backscattering signals of different spheroidization samples are collected through the ultrasonic testing experimental platform, and the root-mean-square (RMS) maximum values of the ultrasonic backscattering are extracted. The observed trend is consistent with the theoretical model, finite element method (FEM), and experimental. Compared with the experimental results, the model results have some errors, but can be used to evaluate the performance degradation of metallic materials with lamellar pearlite structure.

Temperature compensation study of pressure sensors after leadless packaging

Purpose The purpose of this paper is to reduce the problem of temperature drift causing output errors in such sensors, three hardware compensation schemes are proposed in this paper, and three compensation schemes are designed and implemented. Design/methodology/approach In response to the problem of temperature drift causing output errors in this type of sensor, this paper proposes three hardware compensation schemes and carries out the design and implementation of the three compensation schemes. Finally, the advantages and disadvantages of the three compensation schemes are discussed through the analysis of the experimental results. The three hardware compensation methods are series-parallel resistance network compensation, digital signal processor (DSP) compensation and the joint compensation of resistance network and DSP. Series parallel resistance network compensation is to connect the low-temperature drift resistance and the sensor in series and parallel; DSP compensation is based on the combination of cubic spline interpolation and linear fitting algorithm, which uses DSP to process the data. Joint compensation is a new compensation method composed of the above two compensation methods. Findings The experimental results show that the relative error of the output is reduced to a certain extent after the three compensation methods, and the relative error of the output after the joint compensation is reduced to about 0.2%, which proves that the three compensation methods are feasible. Originality/value This paper presents three novel hardware compensation methods to reduce temperature drift in silicon on insulator (SOI) high-temperature pressure sensors. The joint compensation method, combining resistance network and DSP compensation, is particularly innovative and significantly improves output accuracy, reducing relative error to about 0.2%.

Research on Application of diamond MOSFET in DCDC converter

This paper focuses on the industrial application of diamond power devices and DCDC converters, carries out the application research of diamond MOSFET in DCDC converters, analyzes the limitations of current silicon-based DCDC converters and how diamond MOSFET should make up for this limitation. This paper summarizes the research on the practical application of diamond power devices at home and abroad and points out that there is a gap in the application of diamond MOSFETs in DCDC converters. Diamond has the advantages of a large band gap, high carrier mobility, high temperature and high pressure resistance, so the application of diamond MOSFET in a DCDC converter can improve its operating frequency, input and output voltage and efficiency. This paper also discusses the difficulties encountered by diamond semiconductor materials and diamond power devices in the research and industrial fields, as well as the research status of diamond semiconductor materials at home and abroad, and gives the research method for the future application of diamond MOSFET in DCDC converters. The study can use the analogy of applying SiC or GaN to DCDC converters improving their performance, and redesigning the drive circuit to match the limiting performance of diamond power devices. By applying diamond MOSFET into the DCDC converter, its operating voltage, operating frequency, output power and efficiency will be greatly improved.

Numerical Simulation of Gas–Liquid–Solid Erosive Wear in Gas Storage Columns

Gas reservoirs play an increasingly important role in oil and gas consumption and safety in China. To study the problem of erosion and wear caused by gas-carrying particles in the process of gas extraction from gas storage reservoirs, a mathematical model of gas–liquid–solid three-phase erosion of gas storage reservoir columns was established through theories of multiphase flow and particle motion. Based on this model, the effects of the water volume fraction, gas extraction rate, particle mass flow rate, particle size, and bending angle on the erosion location and rate of the pipe columns were investigated. The findings indicate that when the water content volume fraction is low, the water production volume minimally affects the maximum erosion rate of pipe columns. Conversely, the gas extraction rate exerted the most significant influence on the column erosion, showing a power function relationship between the two. When gas extraction volume exceeds 60 × 104 m3/d, the maximum erosion rate surpasses the critical erosion rate of 0.076 mm/a. This coincided with the increased sand mass flow rate, although the maximum erosion rate of the pipe columns remained relatively steady. The salt mass flow rate demonstrated a linear relationship with the erosion rate, with the maximum erosion rate exceeding the critical erosion rate of 0.076 mm/a. The maximum erosion rate of the pipe columns increased, stabilized with larger sand and salt particle sizes, and exhibited an increasing trend with the bending angle. For gas extraction volumes exceeding 46.4 × 104 m3/d and salt mass flow rates exceeding 22 kg/d, the maximum erosion rate of pipe columns exceeds the critical erosion rate of 0.076 mm/a. The conclusions of this study are of some importance for the clarification of the influencing law of pipe column erosion under high temperature and high pressure in gas storage reservoirs and for the formulation of measures for the prevention and control of pipe column erosion in gas storage reservoirs.

Microwave synthesis of molybdenum disulfide quantum dots and the application in bilirubin sensing.

Molybdenum disulfide quantum dots (MoS2 QDs) is a new type of graphite like nanomaterial, which exhibited well chemical stability, unique fluorescence characteristics, and excellent biocompatibility. The conventional hydrothermal synthesis of MoS2 generally requires a long-term reaction at high temperature and high pressure. Herein, we have developed a simple and fast MoS2 QDs synthesis scheme using microwave heating, and further modified the surface of MoS2 QDs using 3-aminophenylboronic acid. The 3- aminophenylboronic acid modified MoS2 QDs (B-MoS2 QDs) were further coated by a zinc-based metal-organic backbone (ZIF-8) in a solution containing zinc ions and 2-methylimidazolium. The constructed nanohybrid B-MoS2@ZIF-8 were successfully applied to the visualization and rapid detection of bilirubin based on the ratiometric fluorescence changes. The linear range for bilirubin detection is 0.2-75 μmol•L-1, and detection limit is 0.017 μmol•L-1.

An investigation into the impact of diapir structures on formation pressure systems: a case study of the Yinggehai Basin, China

Under the influence of diapir structure, the formation pressure system is complicated. The characteristics of high temperature and high pressure are obvious, the prediction is difficult, and complex accidents such as well kick and leakage are frequent, which seriously restrict the efficient development of oil and gas resources. Therefore, taking Yinggehai Basin in China as an example, combined with the evolution characteristics of diapir structure, the influence of diapir structure on abnormal high-pressure, wellhole collapse and fracture is analyzed. Three pressure calculation methods are selected, and the distribution rules of pressures and safety density window are analyzed, too. The results show that the diapir structure and its associated fault not only constitute the fluid transport system, but also make the deep overpressure transfer upward and accumulate into high pressure in the shallow formation, and the development of the associated fault destroy the integrity of the formation rock and reduce the strength of the rock. The upwelling of hot fluid changes the local geothermal conditions, reduces the hydrocarbon generation threshold of shallow source rocks, promotes the evolution of clay minerals, causes hydrothermal expansion, and enhances the shallow high pressure. In high-temperature environment, the cooling effect of drilling fluid will produce heating stress, change the stress distribution around the wellhole, and increase the risk of wellbore instability. Additionally, under the influence of diapir structures, the pore pressure in deep formations increases, while the fracture pressure decreases, resulting in a significantly narrowed safe density window. The safety density window width generally presents a half-spindle shape, and with the increase of depth, the window width increases first and then decreases.

Numerical simulation of cementing seal integrity during electric heating of oil shale

Electric heating technology is a vital method for in-situ modification and exploitation of oil shale. This process subjects the wellbore and cement sheath to prolonged exposure to high temperature and pressure environments, posing significant challenges to the integrity of the cementing seal. To investigate the thermally induced changes during the electric heating process of cement sheath and oil shale, a combined model of cement sheath and oil shale was established using the discrete element method. The combined model was calibrated based on macroscopic mechanical experiments of cement sheath and oil shale. Subsequently, the thermal-mechanical coupling problem and thermal cracking phenomenon of the combined model under high temperature and high pressure environments were examined. The results revealed that thermal cracks begin to emerge at the onset of heating at around 150 °C, leading to a decrease in compressive strength and elastic modulus of the combined body. As the temperature reaches 400 °C to 500 °C, the number of thermal cracks peaks. The underground high-pressure environment impedes the thermal expansion of combined body particles, thereby inhibiting the development of thermally induced cracks. The addition of steel fibers to the cement sheath significantly reduces thermal cracking and effectively enhances the sealing performance of the cement sheath.

Structural and transport properties of (Mg,Fe)SiO3 at high temperature and high pressure

Abstract (Mg,Fe)SiO3 is primarily located in the mantle and has a substantial impact on geophysical and geochemical processes. Here, we employ molecular dynamics simulations to investigate the structural and transport properties of (Mg,Fe)SiO3 with varying iron contents at temperatures up to 5000 K and pressures up to 135 GPa. We thoroughly examine the effects of pressure, temperature, and iron content on the bond lengths, coordination numbers, viscosities, and electrical conductivities of (Mg,Fe)SiO3. Our calculations indicate that the increase of pressure leads to the shortening of the O-O and Mg-O bond lengths, while the Si-O bond lengths exhibit the initial increase with pressure up to 40 GPa, after which it is almost unchanged. The coordination numbers of Si transition from four-fold to six-fold and eventually reaching eight-fold coordination at 135 GPa. The enhanced pressure causes the decrease of the diffusion coefficients and the increases of viscosities of (Mg,Fe)SiO3. The increased temperatures slightly decrease coordination numbers and viscosities, as well as obviously increase diffusion coefficients and electrical conductivities of (Mg,Fe)SiO3. Additionally, iron doping facilitates the diffusion of Si and O, reduces viscosities, and enhances electrical conductivities of (Mg,Fe)SiO3. These findings advance fundamental understanding of the structural and transport properties of (Mg,Fe)SiO3 under high temperature and high pressure, which provide novel insights for unraveling the complexities of geological processes within the Earth's mantle.

Research on carbon dioxide treatment and utilization technology

This paper summarizes the various types of carbon dioxide treatment technology, the current situation, and the development trend, and describes the progress and challenges in the application of carbon dioxide treatment technology at the present stage. It is found that the focus of research and development should be on improving carbon capture efficiency and reducing carbon capture costs. CO2 utilization technology is currently in the industrial demonstration stage, and breaking through the bottleneck of high temperature and high pressure environment, and searching for suitable catalysts to improve the carbon utilization efficiency are the key research directions in the next stage of CO2 utilization technology. CO2 treatment technology needs to overcome the challenges of economic profitability, technological innovation, cost reduction and efficiency enhancement, and policy subsidies and incentives. CO2 bioprocessing technology will become a new mode of CO2 treatment promotion in the future. This study is of reference significance for accurately grasping the research direction of CO2 treatment technology, promoting the progress and innovation of CO2 treatment technology, and accelerating the leapfrog development of CO2 treatment technology.

Effects of alloying elements (Ti, Zr, Ta, W) on the thermodynamic and elastic properties of HfC at high temperature and high pressure

Effects of alloying elements (Ti, Zr, Ta, W) on the thermodynamic and elastic properties of HfC at high temperature and high pressure

Managing negative linear compressibility and thermal expansion through steric hindrance: a case study of 1,2-bis(4'-pyridyl)ethane cocrystals.

Multicomponent crystals have great scientific potential because of their amenability to crystal engineering in terms of composition and structure, and hence their properties can be easily modified. More and more research areas are employing the design of multicomponent materials to improve the known or induce novel physicochemical properties of crystals, and recently they have been explored as materials with abnormal pressure behaviour. The cocrystal of 1,2-bis(4'-pyridyl)ethane and fumaric acid (ETYFUM) exhibits a negative linear compressibility behaviour comparable to that of framework and metal-containing materials, but overcomes many of their deficiencies restricting their use. Herein ETYFUM was investigated at low temperature to reveal negative thermal expansion behaviour. Additionally, a cocrystal isostructural with ETYFUM, based on 1,2-bis(4'-pyridyl)ethane and succinic acid (ETYSUC), was exposed to high pressure and low temperature, showing that its behaviour is similar in nature to that of ETYFUM, but significantly differs in the magnitude of both effects. It was revealed that the minor structural difference between the acid molecules does not significantly affect the packing under ambient conditions, but has far-reaching consequences when it comes to the deformation of the structure when exposed to external stimuli.

Plasma evolution investigation and aging grade evaluation of heat resistant steel based on laser induced plasma image

The accurate evaluation of the heat-resistant steel deterioration by laser-induced breakdown spectroscopy (LIBS) is of great important for the safe operation of high-temperature pressure equipment. Understanding how plasma express matrix...

AQUASYN-X: INNOVATIVE SOBM FOR DRILLING IN EXTREME TEMPERATURE AND PRESSURE CONDITIONS

The development of new synthetic oil-based mud (SOBM) is crucial for enhancing drilling operations in extreme environments, such as deepwater and offshore locations, while maintaining environmental sustainability. This paper presents AquaSyn-X, a next-generation SOBM specifically engineered to withstand the harsh conditions encountered during deepwater and high-pressure, high-temperature (HPHT) drilling operations. The primary objectives of developing AquaSyn-X include improving thermal and pressure stability, minimizing toxicity, and enhancing lubricating properties to ensure efficient drilling performance. AquaSyn-X's formulation is based on a unique combination of synthetic oils, emulsifiers, and rheology modifiers, which provide superior stability and functionality in challenging environments. Results from the experiments show that AquaSyn-X exhibits excellent emulsion stability, even under extreme HPHT conditions. The mud also demonstrates a significant reduction in friction, which leads to enhanced wellbore stability and reduced risks of stuck pipe incidents. The findings indicate that this SOBM is compliant with environmental regulations governing offshore drilling, and its use significantly reduces the release of harmful chemicals into marine ecosystems. This innovative SOBM could lead to improved operational efficiency, reduced downtime, and a smaller environmental footprint, thereby setting a new standard for drilling fluids in the oil and gas industry. Keywords: synthetic oil-based mud (SOBM), high-pressure high-temperature (HPHT), deepwater drilling, environmental sustainability, friction reduction, wellbore stability.

Type-n electrical activations of unintentionally auto-doped N atoms in the CVD diamond films grown on the HPHT Ib substrates, after 4-MeV Si2+ irradiations

This article describes observation of n-type conductivity for chemical vapor deposition (CVD) diamond films annealed by using 4-MeV Si2+ ion-beam irradiation at a low temperature of 660 °C. Although CVD diamond films grown on the High-Pressure High-Temperature (HPHT) Ib-substrates showed excellent crystallinity, these films were unintentionally auto-doped with highly concentrated N atoms. At first, n-type conductivity had not been judged for the as-grown state. However, after irradiation by 4-MeV Si2+ ions at 660 °C, the grown diamond film exhibited clear and stable n-type conductivity at a relatively low temperature of 250 °C. This fact was ascertained by measuring the electrical conductivity with a Hall effect apparatus. The as-purchased HPHT Ib-substrate after a normal RCA cleaning processes exhibited evident n-type conductivity at above 300 °C due to intrinsically contained dopant N atoms in the substrate. On the other hand, the as-grown CVD film deposited on the Ib-substrate exhibited evident n-type conductivity at a thoroughly lower temperature of 250 °C after 4-MeV Si2+ irradiation. 250 °C temperature is lower than 300 °C for the as-purchased HPHT Ib-substrate. Theoretical simulations were performed to fit Hall-measured data of sheet resistivity and sheet carrier concentration. The simulation results were based on the charge neutrality principles. The author also proposed novel activation energy of N atoms in diamond semiconductors to be 2.5 eV, which is much larger than formerly reported values of 1.4–1.7 eV. Lastly, the author discussed the possibility of MeV-ion irradiations being as novel and useful annealing technology for heavy type-n-dopants ion implantations into diamond semiconductors.

Analysis of the influence of post-processing parameters on the curling phenomenon of knitted fabrics using pixel images

Curling is a common phenomenon in knitted fabrics, which can affect production efficiency and quality, and edge curling is greatly affected by dyeing and finishing processes. This article proposes a pixel-analysis-based testing method to quantify edge curling problems and reveal the relationship between curling and dyeing parameters. This study investigated three different colors (white, blue, and black) on the same fabric sample. For each color, three finishing methods were used: no softener, adding softener, and high-temperature setting after adding softener. The results showed that the rolled edges of the fabric were severe, and even without the addition of softener, the rolled edges of all three colors of fabrics were improved significantly after dyeing. The rolled edges of white fabrics are the lightest, whereas the curled edges of blue and black fabrics gradually increase. Softener effectively improves the problem of edge curling by reducing the friction coefficient between yarns, decreasing internal stress in fabrics, and lowering the bending stiffness of yarns. The mechanical effects of high-temperature setting and pressure flatten the fuzz, which can reduce the friction coefficient and bending stiffness of the yarn, and also help improve edge curling.