Browse
Subjects
Records with Subject: Other
Showing records 1 to 25 of 1214. [First] Page: 1 2 3 4 5 Last
Experimental Investigation of Phase Equilibria in the Al−Mo−Hf Ternary System at 400 °C and 600 °C
Boliang Liu, Zhiqiang Yu, Libin Liu, Ligang Zhang
June 24, 2024 (v1)
Subject: Other
Keywords: Al-Mo-Hf system, isothermal section, phase equilibrium, solid solubility
This study investigates the phase equilibria of the Al-Mo-Hf ternary system at 400 °C and 600 °C using X-ray diffraction (XRD) and electron probe microanalysis (EPMA/WDS) techniques. Seven three-phase and five two-phase regions were identified at 400 °C, while eight three-phase and four two-phase regions were identified at 600 °C. Despite variations in the solid solubility ranges of certain compounds, the distribution of phase zones in the isothermal cross-section remained consistent at both temperatures. Using the experimental results and logical deductions, isothermal cross-sections were constructed for the Al-Mo-Hf ternary system at 600 °C and 400 °C.
Research on Inversion Log Evaluation Method of Special Mineral in Alkali Lake Shale Oil Reservoir—A Case Study of the Fengcheng Formation in the Mahu Sag, China
Lei Zhao, Rui Mao, Xili Deng, Ziyan Feng, Junkai Chen, Xianghua Zong, Cheng Feng
June 24, 2024 (v1)
Subject: Other
Keywords: alkaline minerals, combining model, Fengcheng Formation, Junggar Basin, Litho Scanner Log, Mahu Sag, mineral inversion
The Fengcheng Formation in the Mahu Sag of the Junggar Basin, China, is characterized by alkaline lake deposits, featuring abundant alkaline minerals. The content of alkaline minerals affects the physical properties and oil-bearing properties of the reservoir, and existing mineral inversion methods cannot calculate the content of alkaline minerals. Based on Litho Scanner Log data, we can calculate the dry weight of elements using the oxide closure model. By improving the rock volume physical model; adding trona, shortite, eitelite, and reedmergnerite to the rock volume physical model; and combining with the least squares method, the mineral content calculation was carried out, using the inversion method of combination models (Shortite Model, Eitelite Model, Reedmergnerite Model, and Trona Model) to achieve mineral inversion of alkali-bearing shale oil reservoirs. Litho Scanner Log is expensive, and its widespread application will increase exploration costs. This article scales the mine... [more]
Exploitation and Utilization of Generated Oil and Gas by Pyrolysis Simulation Modeling of Shale Source Rocks under the Condition of In Situ Conversion
Xia Luo, Lianhua Hou, Zhongying Zhao, Senhu Lin, Zhenglian Pang, Lijun Zhang, Wenxue Han, Yong Li
June 21, 2024 (v1)
Subject: Other
Keywords: geochemistry, shale, simulation modeling, source rock, unconventional resources
Previous studies have mainly focused on the source rocks of the 7th Member of Yanchang Formation (Chang 7 Member) in the Ordos Basin, with very few studies focusing on the extracts from the source rocks. These extracts have important guiding significance for studying the in situ conversion process of shale oil. Taking the shale source rock of the Chang 7 Member as an example, this paper selected the extract of shale source rock (i.e., retained oil), which has been less studied previously, as the sample to carry out the hydrocarbon-generating pyrolysis simulation experiment of a semi-open−semi-closed system. Seven groups of parallel simulation experiments were designed with a pressure of 20 MPa. The generated oil and gas were collected and quantified, and their geochemical characteristics were researched. In addition, the generated oil and gas were investigated from aspects of cumulative yield and net increased yield, and the chromatographic and mass spectral characteristics of the gene... [more]
Research on Fluid−Solid Coupling Mechanism around Openhole Wellbore under Transient Seepage Conditions
Erhu Liu, Desheng Zhou, Xu Su, Haiyang Wang, Xiong Liu, Jinze Xu
June 10, 2024 (v1)
Subject: Other
Keywords: effective circumferential stress, fluid–solid coupling, open-hole wellbore, pore pressure
Hydraulic fracturing is one of the most important enhanced oil recovery technologies currently used to develop unconventional oil and gas reservoirs. During hydraulic fracture initiation, fluid seeps into the reservoir rocks surrounding the wellbore, inducing rock deformation and changes in the stress field. Analyzing the fluid−solid coupling mechanism around the wellbore is crucial to the construction design of fracturing technologies such as pulse fracturing and supercritical carbon dioxide fracturing. In this study, a new transient fluid−solid coupling model, capable of simulating the pore pressure field and effective stress field around the wellbore, was established based on the Biot consolidation theory combined with the finite difference method. The numerical results are in excellent agreement with the analytical solutions, indicating the reliability of the model and the stability of the computational approach. Using this model, the influence of seepage parameters and reservoir p... [more]
Prevention of Blowout Tests in Large-Diameter Boreholes with Soundless Chemical Demolition Agents and Fracturing Characteristics of Hard Sandstones
Junjie Wu, Zhuo Dong, Ruifu Yuan, Shuaishuai Xie, Junhao Deng
June 10, 2024 (v1)
Subject: Other
Keywords: expansion properties, fracture expansion, internal cooling blowout prevention methods, large-diameter boreholes, soundless chemical demolition agents
Increasing the diameter of the drillhole can facilitate drillhole breakage using soundless chemical demolition agents, but it is prone to cause drillhole blowout, resulting in crushing failure. This paper conducted a blowhole prevention test on a large borehole using the internal insertion cooling pipe method (ICBPM) to test the expansion pressure of cooling pipes with different diameters. During this test, a fracture occurred in a hole with a 75 mm inner diameter in the rectangular sandstone specimens with high strength. It was found that utilizing the ICBPM can effectively hinder the development of blowholes. Expansion and blowhole prevention are optimized with a 0.14 mass ratio of the cooling water to demolition agent and a maximum expansion stress of 49.0 MPa. The guiding effect of the minimum resistance line is significant. In repeated tests, all fissures are distributed in a Y-shape on the free surface where the minimum resistance line is located. The acoustic emission signals fr... [more]
Experimental Investigation of a Pulsation Reactor via Optical Methods
Chunliang Zhang, Jakub Dostál, Stefan Heidinger, Stefan Günther, Stefan Odenbach
June 7, 2024 (v1)
Subject: Other
Keywords: natural flame luminosity, particle image velocimetry, pulsatile flame, pulsatile flow, pulsating combustion, pulsation reactor
Material treatment in pulsation reactors (PRs) offers the potential to synthesize powdery products with desirable properties, such as nano-sized particles and high specific surface areas, on an industrial scale. These exceptional material characteristics arise from specific process parameters within PRs, characterized by the periodically varying conditions and the resulting enhanced heat and mass transfer between the medium and the particulate material. Understanding flame behavior and the re-ignition mechanism is crucial to controlling the efficiency and stability of the pulse combustion process. In order to accomplish this objective, an investigation was conducted into flame behavior within the combustion chamber of a Helmholtz-type pulsation reactor. The study was focused on primarily analyzing the flame propagation process and examining flame velocity throughout the operational cycle of the reactor. Two optical methods—natural flame luminosity (NFL) and particle image velocimetry (... [more]
Numerical Simulation Study on the Damage Mechanism of the Combined Perforating Well Testing Tubing in Ultra-Deep Wells
Jiadong Jiang, Qiao Deng, Dong Yang, Guilin Qi, Fan Zhang, Leichuan Tan
June 7, 2024 (v1)
Subject: Other
Keywords: damage mechanism, dynamics analysis, effective stress, numerical simulation, perforating tubing, petroleum perforation, shock wave, ultra-deep well
During perforation in ultra-deep wells, the blast shock wave can induce dynamic responses of the perforating tubing, leading to potential downhole accidents such as vibration, deformation, and even fracture of the perforating tubing. To comprehend the dynamic response characteristics of the perforating tubing under blast impact load, we conducted a joint finite element simulation using SolidWorks, Hypermesh, and LS-DYNA. The simulation included deformation analysis, motion analysis, and strength analysis of the perforating tubing. By analyzing these factors, we obtained the change in velocity, acceleration, and equivalent stress of the perforating tubing over time under the blast load. The finite element analysis indicates the following: (a) the bottom of the perforating tubing is susceptible to significant tension compression cycle; (b) the velocity amplitude variation is smallest at the top of the perforating tubing, while the frequency and peak values of velocity changes are maximal... [more]
Hydrocarbon Source Rock Evaluation of the Lucaogou Shale in the Periphery of Bogeda Mountain (SE Junggar Basin, China) and Its Implications for Shale Oil Exploration: Insights from Organic Geochemistry, Petrology, and Kinetics Pyrolysis
Guanlong Zhang, Yuqiang Yang, Tianjiao Liu, Youde Xu, Xiangchun Chang, Yansheng Qu, Bingbing Shi, Bo Yang, Tao Song
June 7, 2024 (v1)
Subject: Other
Keywords: Bogeda Mountain, hydrocarbon generation potential, Junggar Basin, kinetics modeling, Lucaogou Formation, thermal history
Since the discovery of the vast Jimusaer shale oilfield in the southeastern Junggar Basin in 2012, there has been considerable interest in neighboring areas around Bogeda Mountain that have shale oil potential. The primary productive interval in the basin, the Middle Permian Lucaogou Formation (P2l), is well-developed in the areas of Qitai, Mulei, Shiqiantan, Chaiwopu, and Miquan. In this study, we conducted an assessment of the hydrocarbon generation potential of the P2l in these five areas and compared it with that of the P2l in the Jimusaer oilfield, which were determined by GC-MS, total organic carbon (TOC) and vitrinite reflectance (Ro) measurements, Rock-Eval pyrolysis, and organic petrology to investigate the type, origin, thermal maturity, hydrocarbon potential, and oil/gas proneness of organic matter in the P2l. Additionally, we applied open-system pyrolysis of hydrocarbon generation kinetics to explore differences in hydrocarbon generation and expulsion across various P2l mud... [more]
Marangoni Convection Velocity in Nonlinear Hanging-Droplet Vibration Phenomena
Koutaro Onoda, Ben Nanzai
June 7, 2024 (v1)
Subject: Other
Keywords: interfacial instability, interfacial tension, Marangoni effect, oscillation
The Marangoni effect involves a mass transfer along an interface between two phases owing to the gradient of the interfacial tension. The flow caused by this phenomenon is called Marangoni convection, a complex phenomenon that involves mass transfer processes, such as surfactant adsorption/desorption processes, solvent dissolution phenomena, and viscous dissipation processes. Therefore, the strength of the convection depends on the various thermodynamic and physical properties of the fluids. In this study, we experimentally investigated the relationship between the Marangoni convection generated inside a hanging oil droplet and the interfacial tension of the oil droplet in an aqueous phase by the particle image velocimetry method. This convection velocity depended on the initial value of the interfacial tension in the oil−water interfacial tension oscillation phenomenon accompanied by the expansion and contraction of the hanging drop. Additionally, the droplet oscillation frequency dec... [more]
Risk Analysis of Wellbore Instability of “Felt Layer” in Qiudong Sag Based on Monte Carlo Method
Ruixue Jia, Liang Zhu, Xiaoping Song, Jian Chen
June 7, 2024 (v1)
Subject: Other
Keywords: collapse pressure, Monte Carlo, reliability, stable borehole, uncertainty
Both domestic and international scholars have conducted in-depth research on wellbore stability issues. They have established various empirical models, analytical models, and numerical simulation methods. However, there is relatively little research on the impact of the uncertainty of input parameters on wellbore stability, and the understanding of this aspect remains unclear. To address this, this paper introduces a probability distribution method. It is based on a wellbore stability mechanical analytical model and, using reliability theory, establishes a method for evaluating wellbore instability risks. By employing the Monte Carlo random simulation method, this study investigates the sensitivity of input parameters to wellbore stability, clarifying that ground stress is the main controlling factor affecting wellbore stability. Combining the analysis of the “felt layer” ground stress profile, this study utilizes two-dimensional simulation experiments to validate the accurate determin... [more]
Influence of Side Duct Position and Venting Position on the Explosion and Combustion Characteristics of Premixed Methane/Air
Junping Cheng, Yongmei Hao, Zhixiang Xing, Rui Song, Fan Wu, Sunqi Zhuang
June 7, 2024 (v1)
Subject: Other
Keywords: explosion characteristics, methane/air, side duct position, venting
In order to explore the influence of the side duct position and venting position on the premixed combustion and explosion characteristics of methane/air, a premixed combustion and explosion experiment of methane/air and a simulation of an explosion of the same size were carried out in a tube with an internal size of 2000 mm × 110 mm × 110 mm. The results showed that the side duct could change the flame structure and accelerate the flame inside the tube. The maximum increase ratio of the flame propagation speed was 106.1%. The side duct had a certain venting effect on the explosion pressure. For different position cases, when the venting film was placed over the bottom section, the maximum overpressure first decreased and then increased. When the venting film was placed over the middle section and the top section, the maximum overpressure first increased and then decreased, and the change trend of the top section was stronger. Turbulence mostly occurred inside the side duct when the ven... [more]
An Injection-Mold Based Method with a Nested Device for Microdroplet Generation by Centrifugation
Jichen Li, Wen Li, Bizhu Wu, Wenting Bu, Miaomiao Li, Jinyan Ou, Yuxiang Xiong, Shangtao Wu, Yanyi Huang, Yong Fan, Yongfan Men
June 7, 2024 (v1)
Subject: Other
Keywords: centrifuge-based, fluorescent hydrogel microspheres, injection molding, microdroplet generation
Microdroplets have been widely used in different fields due to their unique properties, such as compartmentalization, single-molecule sensitivity, chemical and biological compatibility, and high throughput. Compared to intricate and labor-intensive microfluidic techniques, the centrifuge-based method is more convenient and cost-effective for generating droplets. In this study, we developed a handy injection molding based method to readily produce monodisperse droplets by centrifugation. Briefly, we used two three-dimensional (3D) printed master molds with internal cavities to forge two coupled sub-molds by injecting polydimethylsiloxane (PDMS) and casted these two PDMS sub-molds into a nested structure that clamps the micro-channel array (MiCA) by injecting polyurethane resin. This method enables the generation of various sizes of monodispersed microdroplets by centrifugation with proper parameters within 10 min. To assess the performance of this method, homogeneous fluorescent hydroge... [more]
Description of Pore Structure of Carbonate Reservoirs Based on Fractal Dimension
Youyou Cheng, Xiang Luo, Qingong Zhuo, Yanjie Gong, Liang Liang
June 6, 2024 (v1)
Subject: Other
Keywords: carbonate rock, fractal dimension, microscopic description, permeability, reservoir characteristics
The complexity and heterogeneity of pore structures in carbonate reservoirs pose significant challenges for accurately characterizing the influence of different pore micro-parameters on reservoir physical properties. Drawing upon the principles of fractal geometry theory applied to reservoir rocks, this study combines mercury intrusion porosimetry (MIP) and nuclear magnetic resonance (NMR) T2 spectrum methods to explore the relationship between the fractal dimension and micro-parameters of pore throats at various scales. Additionally, it clarifies how the fractal dimension of pores at different scales impacts reservoir physical properties. Moreover, a permeability prediction model that incorporates fractal dimensions is developed. The findings demonstrate that the fractal dimension effectively captures the complexity and multi-scale nature of reservoir microstructures, leading to higher reliability in predicting permeability when using the model incorporating the fractal dimension. It... [more]
Study of Acid Fracturing Strategy with Integrated Modeling in Naturally Fractured Carbonate Reservoirs
Xusheng Cao, Jichuan Ren, Shunyuan Xin, Chencheng Guan, Bing Zhao, Peixuan Xu
June 6, 2024 (v1)
Subject: Other
Keywords: acid fracturing, integrated modeling, naturally fractured carbonate, stimulation strategy
Natural fractures and wormholes strongly influence the performance of acid fracturing in naturally fractured carbonate reservoirs. This work uses an integrated model to study the effects of treatment parameters in acid fracturing in different reservoir conditions. Hydraulic fracture propagation, wormhole propagation, complex fluid leak-off mediums, and heat transfer are considered in the modeling. The model is validated in several steps by analytical solutions. The simulation results indicated that natural fractures and wormholes critically impact acid fracturing and can change the predicted outcomes dramatically. The high permeability reservoirs with conductive natural fractures or low permeability reservoirs with natural fracture networks showed the highest stimulation potential in applying acid fracturing technology. The optimal acid injection rate depends on natural fracture geometry and reservoir permeability. This study also observed that obtaining a high production index is diff... [more]
Simulation and Control Strategies for Longitudinal Propagation of Acid Fracture in a Low-Permeability Reservoir Containing Bottom Water
Song Li, Yu Fan, Yujie Guo, Yang Wang, Tingting He, Hua Zhang, Jiexiao Ye, Weihua Chen, Xi Zhang
June 5, 2024 (v1)
Subject: Other
Keywords: acid fracturing, bottom-water gas reservoir, ground stress difference, longitudinal fracture propagation, stimulation
The reservoir in the Anyue gas field, located in the Sichuan basin of China, belongs to the second member of the Dengying formation and has distinctive geological features. It is characterized by strong heterogeneity, low porosity, low permeability, and locally developed natural fractures. The reservoir space consists primarily of corrosion holes, natural fractures, and similar voids. Moreover, the lower reservoir exhibits high water saturation and a homogeneous bottom-water interface. Since it is a carbonate-based hydrocarbon reservoir with low porosity and permeability, deep acid fracturing has proven to be an efficient method for enhancing individual well production. However, the reconstruction of the second member of the Dengying formation reservoir poses significant challenges. The reservoir contains high-angle natural fractures, small vertical stress differences, and is located in close proximity to the gas−water interface. As a result, it becomes difficult to control the height... [more]
Gas-Flow-Rate Inversion Based on Experiments and Simulation of Flame Combustion Characteristics in a Drilling Blowout
Xuliang Zhang, Xiao Liu, Wenxin Huang, Junjie Hu, Yonghong Du, Dongwei Ge, Xiaohui Sun
June 5, 2024 (v1)
Subject: Other
Keywords: blowout, gas-flow-rate inversion, jet flame, numerical simulation
Accurately estimating the gas-flow rate at a wellhead to invert the formation pressure and production capacity information can be the basis for subsequent well-killing parameter design following oil and gas-well drilling blowout and ignition. Based on the multicomponent characteristics of the blowout gas and the turbulence intensity of the blowout flame, as well as the effects of complex factors such as environmental wind direction, wind speed, and wellhead structure, a numerical model for actual drilling blowout ignition is established. Jet-flame experiments are conducted under blowout conditions to verify the accuracy of the model. The temperature and radiation fields and flame morphologies of the well jet flow flame under different lateral wind speeds, well jet flow rates, and wellhead diameters are analyzed. Previous studies have found that as the lateral wind speed increases, the maximum temperature and maximum thermal radiation intensity of the blowout flame first decrease and th... [more]
Effect of Acid-Injection Mode on Conductivity for Acid-Fracturing Stimulation in Ultra-Deep Tight Carbonate Reservoirs
Jiangyu Liu, Dengfeng Ren, Shaobo Feng, Ju Liu, Shiyong Qin, Xin Qiao, Bo Gou
June 5, 2024 (v1)
Subject: Other
Keywords: acid-fracture morphology, acid-injection mode, conductivity, field application, multi-stages alternating acid fracturing, ultra-deep carbonate reservoirs
The conductivity of acid-etched fractures and the subsequent production response are influenced by the injection mode of the fracturing fluid and acid fluid during acid fracturing in a carbonate reservoir. However, there has been a lack of comprehensive and systematic experimental research on the impact of commonly used injection modes in oilfields on conductivity, which directly affects the optimal selection of acid-fracturing injection modes. To address this gap, the present study focuses on underground rock samples, acid systems, and fracturing fluid obtained from ultra-deep carbonate reservoirs in the Fuman Oilfield. Experimental investigations were conducted to examine the conductivity of hydraulic fractures etched by various types of acid fluids under five different injection modes: fracturing fluid + self-generating acid or cross-linked acid; fracturing fluid + self-generating acid + cross-linked acid. The findings demonstrate that the implementation of multi-stage alternating a... [more]
Experimental Investigation of Phase Equilibria in the Al−Mo−Hf Ternary System at 400 °C and 600 °C
Boliang Liu, Zhiqiang Yu, Libin Liu, Ligang Zhang
June 5, 2024 (v1)
Subject: Other
Keywords: Al-Mo-Hf system, isothermal section, phase equilibrium, solid solubility
This study investigates the phase equilibria of the Al-Mo-Hf ternary system at 400 °C and 600 °C using X-ray diffraction (XRD) and electron probe microanalysis (EPMA/WDS) techniques. Seven three-phase and five two-phase regions were identified at 400 °C, while eight three-phase and four two-phase regions were identified at 600 °C. Despite variations in the solid solubility ranges of certain compounds, the distribution of phase zones in the isothermal cross-section remained consistent at both temperatures. Using the experimental results and logical deductions, isothermal cross-sections were constructed for the Al-Mo-Hf ternary system at 600 °C and 400 °C.
Combustion Characteristics, Kinetics and Thermodynamics of Peanut Shell for Its Bioenergy Valorization
Jialiu Lei, Xiaoyu Liu, Biao Xu, Zicong Liu, Yongjun Fu
June 5, 2024 (v1)
Subject: Other
Keywords: combustion characteristics, isoconversional methods, kinetics and thermodynamics, peanut shell, thermogravimetric analysis
To realize the utilization of peanut shell, this study investigates the combustion behavior, chemical kinetics and thermodynamic parameters of peanut shell using TGA under atmospheric air at the heating rates of 10, 20, and 30 K/min. Results indicate that increasing the heating rate leads to higher ignition, burnout, and peak temperatures, as observed in the TG/DTG curves shifting to the right. Analysis of combustion performance parameters suggest that higher heating rates can enhance combustion performances. Kinetic analysis using two model-free methods, KAS and FWO, shows that the activation energy (Eα) ranges from 93.30 to 109.65 kJ/mol for FWO and 89.72 to 103.88 kJ/mol for KAS. The data fit well with coefficient of determination values (R2) close to 1 and the mean squared error values (MSE) less than 0.006. Pre-exponential factors using FWO range from 2.19 × 106 to 8.08 × 107 s−1, and for KAS range from 9.72 × 105 to 2.25 × 107 s−1. Thermodynamic analysis indicates a low-energy ba... [more]
Temporary Plugging Agent Evaluation Technology and Its Applications in Shale Reservoirs in the Sichuan Basin
Liang Wang, Jian Yang, Junliang Peng, Huifen Han, Yang Wang, Zefei Lv
February 19, 2024 (v1)
Subject: Other
Keywords: particle-size optimization, shale oil, Sichuan Basin, temporary blocking and turning in fracturing, temporary plugging agent
Shale oil reservoirs in the Daanzhai section of central Sichuan are mainly developed in the Daer subsection, with a rich resource base and great exploration and development potential. However, the shale oil reservoir is characterized by shale and limestone interactions, poor physical properties, undeveloped fractures, and large differences in the fracture pressure of interactive reservoirs. Therefore, it is necessary to use temporary plugging and diverting fracturing technology to improve the complexity of fractures in reservoir reconstruction. To this end, an experimental device was innovatively established that takes into account the morphology of fractures and the permeability of reservoirs, and it can evaluate the temporary blocks and turns within third-level fractures in a reservoir. It can simulate third-level turning fractures under conditions involving 3−15 mm crack openings and different roughness values. Using this device and method, the combination and particle-size optimiza... [more]
TBM Rapid Tunneling Roadway Support Parameters Design and Process Research
Tao Hou, Zhonghui Xie, Ling Zhang, Guogang Cui, Ziwei Ding, Huafu Qiu, Yuhang Li
February 10, 2024 (v1)
Subject: Other
Keywords: parameter design, rapid tunneling, roadway support scheme, surrounding rock deformation, tunneling process optimization
Taking the specific production geological conditions of the auxiliary transportation lane in the west area of Gaojiabao coal mine of Shaanxi Zhengtong Coal Industry as the research background, based on the anchorage support theory and the characteristics of the TBM digging process, numerical simulation, theoretical analysis, and other research methods were used to investigate the depth of the destruction of the plastic zone of the surrounding rock of the roadway to form the reasonable support parameters of a large cross-section of hard rock roadway suitable for TBM digging and to propose an intelligent digging and support process of the TBM corresponding to the on-site practice. The proposed intelligent tunneling support technology corresponds to a field practice of TBM. The study shows that: combined with the field industrial test and adjusted by the peripheral rock deformation and damage law, the anchor diameter of 20 mm, the length of 2500 mm left-hand threaded steel anchors, row sp... [more]
Application of Three-Dimensional Printing Technology to the Manufacture of Petroleum Drill Bits
Baxian Liu, Yifei Wang, Junjie Jiang, Bihui Zhang, Jian Zhou, Kuilin Huang
February 10, 2024 (v1)
Subject: Other
Keywords: 3D printing, machining accuracy, mold forming, petroleum drill bit, rate of penetration
Drill bits are the main rock-breaking tools in the petroleum and gas industry. Their performance directly affects the quality, efficiency, and cost of drilling. Drill bit manufacturing mainly employs traditional mold forming processes such as milling molding and press molding, which have low production efficiency and long processing cycles and are not conducive to rapid responses to field requirements. Inadequate production accuracy makes it difficult to produce drill bits with complex structures. Three-dimensional (3D) printing technology has fast molding speeds and high molding accuracy. In this paper, 3D printing was applied for the first time to the manufacture of molds for carcass polycrystalline diamond compact (PDC) drill bits and PDC−cone hybrid drill bits. In comparison with forging and milling molding, 3D printing improved production efficiency. The manufactured molds had higher machining accuracy. The ability of 3D printing to make molds with complex surfaces enables the dev... [more]
Flow Visualisation and Evaluation Studies on Metalworking Fluid Applications in Manufacturing Processes—Methods and Results
Udo Fritsching, Lizoel Buss, Teresa Tonn, Lukas Schumski, Jurgen Gakovi, Johnson David Hatscher, Jens Sölter, Kerstin Avila, Bernhard Karpuschewski, Julian Frederic Gerken, Tobias Wolf, Dirk Biermann, Christian Menze, Hans-Christian Möhring, Elio Tchoupe, Lukas Heidemanns, Tim Herrig, Andreas Klink, Kaissar Nabbout, Martin Sommerfeld, Fabian Luther, Ingo Schaarschmidt, Andreas Schubert, Markus Richter
February 10, 2024 (v1)
Subject: Other
Keywords: flow visualisation, high-speed imaging, manufacturing process, metalworking fluid, particle image velocimetry, shadowgraphy
Metalworking operations rely on the successful application of metalworking fluids (MWFs) for effective and efficient operation. Processes such as grinding or drilling often require the use of MWFs for cooling, lubrication, and chip removal. Electrochemical machining processes require electrolyte flow to operate. However, in those machining operations, a fundamental understanding of the mode of action of MWF is lacking due to the unknown flow dynamics and its interaction with the material removal during the process. Important information on the behaviour of MWFs during machining can be obtained from specific experimental flow visualisation studies. In this paper, promising flow visualisation analysis techniques applied to exemplary machining processes (grinding, sawing, drilling, and electrochemical machining) are presented and discussed. Shadowgraph imaging and flow measurements, e.g., particle image velocimetry, allow the identification of typical flow and MWF operating regimes in the... [more]
Hierarchical Optimization Based on Deep Reinforcement Learning for Connected Fuel Cell Hybrid Vehicles through Signalized Intersections
Hongquan Dong, Lingying Zhao, Hao Zhou, Haolin Li
January 12, 2024 (v1)
Subject: Other
Keywords: fuel economy, hierarchical joint optimization, hydrogen fuel cell hybrid vehicle, traveling efficiency, urban roads driving scenario
With the advantages of non-pollution and energy-saving, hydrogen fuel cell hybrid vehicles (HFCHVs) are regarded as one of the potential traveling ways in the future. The energy management of FCHVs has a huge energy-efficient potential which is combined with the Internet of Things (IOT) and auto-driving technologies. In this paper, a hierarchical joint optimization method that combines deep deterministic policy gradient and dynamic planning (DDPG-DP) for speed planning and energy management of the HFCHV is proposed for urban road driving scenarios. The results demonstrate that when the HFCHV is operating in driving scenario 1, the traveling efficiency of the DDPG-DP algorithm is 17.8% higher than that of the IDM-DP algorithm, and the hydrogen fuel consumption is reduced by 2.7%. In contrast, the difference in the traveling efficiency and fuel economy is small among the three algorithms in driving scenario 2, the number of idling/stop situations of the DDPG-DP algorithm is reduced compa... [more]
A Compact Microwave-Driven UV Lamp for Dental Light Curing
Siyuan Liu, Yuqing Huang, Qinggong Guo
January 12, 2024 (v1)
Subject: Other
Keywords: dental light curing, Drude mode, microwave-driven UV lamp, miniaturization
The size of current microwave-driven UV lamps limits their direct application in dental light curing. This article proposes a coaxial structure to miniaturize the UV lamp. First, the Drude model and the finite difference time domain algorithm were used to analyze the multi-physical field coupling and the complex field distribution within the lamp. Second, the dimensional parameters of the lamp were optimized, which enabled the lamp to be miniaturized and operate with high performance. Third, to analyze the sensitivity of the lamp, the effects of input power, gas pressure, and gas composition on its performance were investigated. It was found that an input power of 6 watts was enough to light the bulb with over 90% energy utilization. Finally, to verify the feasibility, an experimental system was set up. The lamp was successfully lit in the experiment, and its spectral output was tested. The results show that the microwave-driven UV lamp based on a coaxial structure is miniaturized and... [more]
Showing records 1 to 25 of 1214. [First] Page: 1 2 3 4 5 Last
[Show All Subjects]