Porosity Distribution Research Articles

Complex shapes of lithium disilicate glass-ceramics developed by material extrusion

The fabrication of high-end ceramics by additive manufacturing gained increasing research interest due to the capacity of these techniques to break through the limitations of traditional extractive manufacturing. Although efficient strategies for the processing of ceramic materials by additive manufacturing have been shown, with notable examples in the dental field, the processing of dense glass-ceramics by the same means is almost unexplored. Herein, a processing strategy for the manufacture of complex shapes of lithium disilicate glass-ceramics by material extrusion is detailed shown for the first time. An aging behaviour was observed on the glass loaded aqueous suspensions and in-deep studied, being related with the leaching of Li+ ions. Based on this, a hydrogel-based ink with high solid content (ϕ≈ 50 vol%), suitable rheological properties (G´≈106 and τ ≈ 1500 Pa) and recovery time was developed. By using the optimized ink, a propeller component with high aspect ratio and small internal connected channels, as well as a dental crown were successfully printed. A debinding schedule was tuned by the combination of differential thermal analysis and hot stage microscopy. The sintered lithium disilicate glass-ceramic parts presented good relative density (≈ 96.7 ± 0.8%) and translucency. Outstanding mechanical properties were achieved (Hv ≈5.3 GPa, KIf ≈2.1 MPa.m0.5, σ ≈ 279 ± 44 MPa), comparable to values usually attained for these materials by powder technology. The low deviation of the flexural strength data reported here is related with the absence of meaningful processing defects on the analysed fracture surfaces and the homogeneous distribution of the residual porosity as microporous, resulting in a good Weibull characteristic strength σ0 = 301 MPa. The results of the present work emphasized the potential of Direct ink Writing, a material extrusion technique, to fabricate lithium disilicate glass-ceramic parts with complex geometries, as dental crowns.

Influência da energia de compactação nas propriedades do concreto permeável e na distribuição vertical da porosidade

Abstract Compaction is a fundamental step in pervious concrete production and affects its mechanical and hydraulic properties. In this study, two pervious concrete mixtures were compacted with three different energies, distributed in two and three layers. The effects on porosity, mechanical strength and hydraulic conductivity were evaluated. The increase in compaction energy resulted in a proportional reduction in porosity. Increases in compressive strength from 17 to 36% were observed. However, permeability reduced proportionally, with decreases of 0.2 to 0.4 cm/s. The three-layer compaction resulted in a more homogeneous vertical distribution of porosity when compared to the two-layer compaction. Although the aggregate/cement ratio was the most influential parameter, the compaction energy should also be considered in the pervious concrete mixture design. While increasing the compaction energy enhances the mechanical strength of pervious concrete, excessive compaction may cause the fracture of the coarse aggregate, reducing its mechanical and hydraulic performance. Thus, for each mixture an optimum compaction energy can be defined to maximize the performance of pervious concrete.

The structure of the pore space of Tournaisian reservoir rocks in the southeast of Tatarstan Republic

The article shows the main types of structures of the porosity of the Tournaisian reservoirs from the southeast of Tatarstan. The main type of pore space is intergrain porosity, while the fractures have a subordinate significance. They are analyzed in detail main factors of the origin of the pore space of the Tournaisian reservoir rock. There are include depositional, diagenetic, structural and tectonically factors. The depositional factor is the selectivity of rock types as reservoirs, only two lithological types of limestone have industrially significant reservoir properties and represented by peloidal and crinoid-peloidal packstones. The diagenetic factor realizes via secondary leaching of carbonate rocks during burial diagenesis of rocks. Leaching processes provide the main increase in rock porosity. On the one hand, the structural and tectonic factor provides the possibility of oil charge in the structure, on the other hand, it shows the heterogeneity of the distribution of porosity depending on the position of the reservoir rocks on the structure. The highest porosity values are characteristic for the crest part, lower for the flanks and minimal for the deflections of the oil-bearing structures.

Experimental and numerical analysis of uni-axial buckling of single-phase functionally graded porous polymeric sandwich plates

The porosity gradient functionally graded material (PFGM) is one of the most popular types of FGM, in which the porosity in the material is made to change in the specified direction. This study looks into the buckling problems of rectangular sandwich plates made of single-phase porous functionally graded materials (PFGMs), commonly used in aircraft structures and biomedical applications. A compression test was performed on the 3D-printed polymeric FG specimens bonded with two thin solid face sheets on the upper and lower surfaces. The critical stress of well-designed and fabricated 3D printed FGM plate samples with various metal core types is determined using a PC installed on universal testing equipment (UTM). The effect of different essential parameters (such as porous ratio, gradient exponent, and aspect ratio) on buckling load and total deformation were explored.The finite element method (FEM) was used to run a numerical simulation on elastic buckling using ANSYS 2021 R1 software to validate the experimental results. The load-displacement relationships and deformed morphologies were investigated using experiments and numerical analysis. The topology arrangement and relative density of the polymer core were examined using the SEM micro-tomography test based on porosity distribution to check the resistance of the sandwich to buckling load. PETG/Al sandwich plates have been found to have critical buckling loads that are 2.52 % higher than PLA/Al sandwich plates, while TPU/Al sandwich plates show increased essential loads of buckling of 5.139 %. The FEM and experiment results show that the existence of porosity in the PLA core in the PFGM plate can reduce the buckling strength tremendously, about 10.52% and 6.8 %, respectively. It was evident that the numerical results show a good agreement with the experimental findings, with a maximum discrepancy of no more than 12 % occurring at the (TPU/Al) sandwich plate with a porosity of 30%.

Recycled waste groundnut oil: A potential feedstock for green energy/biodiesel synthesis

This work focuses on the recycling of waste groundnut oil as a potential feedstock for biodiesel production using activated coconut husk as a regenerating agent. The coconut husk was functionalized using organic acid. The properties of the functionalized coconut husk were investigated via instrumental analysis. Non-parametric modeling involving 2-degree isotherm models were used. The regeneration/recycling of the waste oil were done in batch mode examining key factors of temperature, time, concentration and dosage. Biodiesel was synthesized from recycled waste groundnut oil using transesterification reaction. The properties of biodiesel were examined using ASTM and AOAC official standards. Brunauer-Emmett-Teller surface analysis revealed the surface area of the adsorbent as 371.88 m2/g and a porosity distribution of 0.567 η on the surface at a pH of 6.1. Batch mode analysis revealed that 97.5% of impurities was removed from waste groundnut oil under one batch process at 80 °C after 4 h with 6 g of the activated coconut husk. Langmuir isotherm model provided the best fit to the experimental data with adsorption capacity of 33.5 mg/g at R2 of 0.996. Adsorption of waste groundnut oil impurities onto activated coconut husk was endothermic, as evidenced by the calculated ΔH of +2.7914 kJ/mol. A high cetane number of 48.4 obtained after transesterification is an indication of the good ignition quality of the obtained recycled waste groundnut oil methyl ester. Kinematic viscosity and acid value were revealed to be 4.65 mm2 S−1 and 0.31 mg KOH/g, while the calorific value stood at 38,053 kJ/kg. GC-MS analysis revealed a complex mixture of fatty acid methyl esters dominated by unsaturated fatty acids (58.78%). Recycling of waste cooking oil in this work using activated coconut husk demonstrated good quality as a regenerating agent. The properties of biodiesel obtained showed that it has all the good qualities comparable to other existing biodiesel based on the ASTM and AOAC official standards. More work on the recycling of other waste cooking oils for green energy synthesis to protect our environment from pollution emanating from the use of conventional petro-diesel and promote energy transition is highly recommended.

Advanced Geostatistical Techniques for Building 3D Geological Modeling: A Case Study from Cretaceous Reservoir in Bai Hassan Oil Field

A 3D Geological model was generated using an advanced geostatistical method for the Cretaceous reservoir in the Bai Hassan oil field. In this study, a 3D geological model was built based on data from four wells for the petrophysical property distribution of permeability, porosity, water saturation, and NTG by using Petrel 2021 software. The geological model was divided into a structural model and a property model. The geological structures of the cretaceous reservoir in the Bai Hassan oil field represent elongated anticline folds with two faults, which had been clarified in the 3D Structural model. Thirteen formations represent the Cretaceous reservoir which includes (Shiranish, Mashurah, U.kometan, Kometan Shale, L. Kometan, Gulneni, Dokan, Mauddud, Jawan/Mud, Batiwah, Shuaiba, Garagu, L.Sarmord). According to the property model, the model for each petrophysical property was constructed based on core data and CPI. By using the geostatistical method, the property model was constructed. The Mauddud Formation is considered one of the most promising hydrocarbon reservoirs in the Bai Hassan oil field based on the results of the property model, where the ratio of water saturation is around 30%, the porosity value is reaching up to 31%, and the net to gross ratio is averaging at 70%.

Wave propagation in beams with functionally graded porosity distribution under highly transient axial and transverse impacts

Recent advances in the manufacturing process provide a possibility of fabricating a new generation of porous materials denoted by functionally graded porous materials (FGPM). This paper aims to present a time domain analysis of wave propagation through the porous structures with functionally graded porosity distribution, which has not been completely studied before. For this purpose, the beams with different functionally graded porosity distributions subjected to both axial and transverse tip impact loads with a high-frequency content are investigated. The shear deformable cantilevered functionally graded porous beams with various porosity distributions through the beam thickness are studied. The governing differential equations are derived using the Hamiltonian principle based on the Timoshenko beam theory. A locking-free first-order shear deformable beam element is used to derive the finite element formulation of the equations. The Newmark time integration method is used to perform a time domain analysis of the equations of motion and to investigate the transient response of the beams. The axial and transverse wave propagation characteristics through functionally graded (FG) porous beams are found using time domain analysis of the results. Deflection and velocity time histories of the tip and each point of the beam, reflection time, and variation of support reactions are obtained. The influences of the porosity magnitude and porosity distribution on the wave propagation characteristics and overall time responses are investigated. The results reveal that porosity distribution has a significant effect on the wave amplitude, wave speed, and reflection from the boundary. Also, this study can help in a better understanding of porous structures' behavior subjected to high-transient impact loads in different engineering applications.

Analysis of Stability and Oscillations of Porous Power and Sigmoid Functionally Graded Sandwich Plates by the R-Function Method

In this paper, the R-function method is used for the first time to study the stability and oscillations of porous functionally graded (FG) sandwich plates with a complex geometric shape. It is assumed that the outer layers of the plate are made of functionally graded materials (FGM), and the filler is isotropic, namely ceramic. The differential equations of motion were obtained using the usual first-order shear deformation theory with a given shear coefficient (FSDT). Two models of porosity distribution according to the power (P-law) and sigmoid (S-law) laws were studied. Analytical expressions for calculating the effective mechanical characteristics of FG materials with even and uneven porosity distribution were obtained. The proposed approach takes into account the fact that the subcritical state of the plate can be heterogeneous, and therefore, first of all, the stresses in the middle plane of the plate are determined, and then the eigenvalue problem is solved in order to find the critical load. To determine the critical load and plate frequencies, the Ritz method was used along with the R-function method. The developed algorithms and software are tested on test examples and compared with known results obtained using other methods. A number of problems of stability and oscillations of the FG of porous sandwich plates with a complex geometric shape for various layer stacking schemes, various boundary conditions and laws of porosity distribution have been solved.

The random thermo-elastic nonlinear vibration analysis of porous FGM nano-beams using the first order perturbation theory

The objective of present work is to study the nonlocal nonlinear thermo-elastic vibrations of porous nanobeams made up of functionally graded material (FGM) with random material properties. The mechanical properties of the nano-beam are calculated using a porosity based power law model by assuming the cosine type porosity distributions. The randomness present in the material properties cause the mechanical characteristics of the nano-beams to be random, hence first order perturbation theory has been employed to take care of this randomness. The Reddy’s beam theory in association with the Eringen’s non classical elasticity has been used to account for nonlocal effects, and Von-karman nonlinearity has been employed to take care of geometric nonlinearity. The governing equations are derived from the minimum potential energy principle and solved them using the finite element method. To validate the present model, a convergence and comparison study has been performed. Further, the effects of amplitude ratio, aspect ratio, uncertain material properties, size parameter, porosity, thermal environment, and gradation of material on the stochastic behavior of the porous FGM nano-beams are demonstrated. As a result of the present research, the significance of considering thermal environment, porosity, and random material properties has been revealed for the design of nanodevices and systems to be more reliable.

The evolution of the compaction process and the deformed state of porous blanks during their hot forging in the open die

The article presents the results of the study of the evolution of the deformed state of the workpieces, the energetic parameters of the process and the distribution of porosity over the volume of the forging at all stages of hot forging of porous powder forgings in an open die. Modeling of the process was carried out using the finite element method using the DEFORM 2D/3D software complex. As a result of the simulation, it was found that at the initial stage of the process, the blank is mainly compacted with minimal radial flow of the material. Noticeable flow of metal into the groove groove area begins only when the forging material reaches an average relative density exceeding 90%. A significantly different nature of the distribution of axial er and radial ez deformations over the volume of the forging was noted. A zone with increased levels of values of axial deformations is formed in the central layer of the forging, equidistant from the upper and lower surfaces of the die cavity, and the values of radial deformations decrease with distance from the zone bordering the free side surface of the workpiece in the radial (to-center) direction. The minimum values of ez and er appear in the upper and lower angular stagnant zones of the forging. It is shown that the graph of the dependence of the deformation force on the displacement of the punch is marked by the presence of at least three characteristic sections due to the relationship between the processes of compaction and forging shape change at each stage of the process.

Simultaneous optimal tri-directional distribution of material and porosity in functionally graded plates under free vibration

This paper for the first time attempts to find the simultaneously optimal three-dimensional distribution of porosity and material phases in functionally graded materials (FGMs) model that altogether maximize the natural frequency of porous FG plates. By using the same concept of non uniform rational B-splines (NURBS) based interpolation for the material distribution, the problem of finding the optimal porosity distribution is enabled. An upper bound of porosity is pointed out, which is necessary for considering the porosity design variables. Generalized shear deformation theory (GSDT) in the framework of isogeometric analysis (IGA) for free vibration analysis of the porous FG plates is verified with previous works. The findings are: in the optimal design of material only, the uniformly distributed pores have a neutral or detrimental effect on 4-side constrained plates but slightly increase the frequency for the cantilever plate; and with that same amount of porosity, the simultaneously optimal distributions of pores, similar to those in bio-materials or natural bones in the way that are most foam-like in the center or at the furthest from the boundaries, result in lighter yet of significantly elevated vibration frequency structures.

The effect of the various porous layers on thermomechanical buckling of FGM sandwich plates

This study focuses on the thermal buckling behavior of sandwich porous plates made up of metal-ceramic functionally graded material (FGM) components using a new sinusoidal high order shear theory. The sandwich plate consists of a core plate made of either pure metal or pure ceramic, with face layers composed of a functional gradient of metal and ceramic constituents. This study examined the porosity and four porosity distribution functions in plates with FGM face layers and nonlinear temperature increase and material grading index of the face layers on the thermal buckling loads of sandwich plates.

Controlled Morphology Direct Iron Reduction from an Alkaline Slurry of Hematite for a Low-Cost Energy Storage Technology

Iron-air batteries became a promising research direction for low-cost and long-duration energy storage. Moreover, extensive work on iron-related technologies can assist in the decarbonization of the steelmaking industry.1 To mitigate the issue of a parasitic hydrogen evolution reaction that significantly lowers the high theoretical specific capacity of the device, grafted Fe/C, as well as carbonyl-iron composite electrodes were studied.2 Despite the effectiveness of such methods and commercialization success, the complicated nature of a starting material makes it costly for plant-scale production. In this work, we are presenting the iron-plating method under alkaline conditions which is aimed to produce various morphology anodes for improved cycling in a pouch-cell with a perspective usage in the iron-air storage technology. This preparation approach of the battery component from abundant metal could replace the more emission-intensive technologies being used today. Additionally, a study on zinc monolithic anodes has proven to dramatically elevate the performance of the primary and secondary devices predicting a similar success for various metals.3 In the first cycle of the research, we discover how the faradaic efficiency and specific capacity of direct iron metal deposition from the iron (III) oxide slurry are impacted by varying temperatures of the process. Additionally, changes in the morphology and the porosity distribution are observed based on the initial controlled hematite particle size. The second cycle is dedicated to the cycling behavior of the prepared anodes. By performing a set of characterizations, we are able to account for the factors influencing the final performance of the prepared anodes. These findings allow us to better understand the feasibility of such a preparation method of the iron anode for an alternative energy storage scale-up. Woodford, W. H.; Burger, S.; Ferrara, M.; Chiang, Y.-M., The iron-energy nexus: A new paradigm for long-duration energy storage at scale and clean steelmaking. One Earth 2022, 5 (3), 212-215.Hang, B. T.; Eashira, M.; Watanabe, I.; Okada, S.; Yamaki, J.-I.; Yoon, S.-H.; Mochida, I., The effect of carbon species on the properties of Fe/C composite for metal–air battery anode. Journal of Power Sources 2005, 143 (1-2), 256-264.Joseph F. Parker, C. N. C., Irina R. Pala, Meinrad Machler, Michael F. Burz, Jeffrey W. Long, Debra R. Rolison, Rechargeable nickel–3D zinc batteries: An energy-dense, safer alternative to lithium-ion. Science 2017, 356, 415–418.

Highly Porous Fe3O4/Graphene Aerogels for Enhanced Lithium Storage

A facile and green method was adopted to produce iron oxide/graphene composite which can be used as free-standing and additive-free electrodes in lithium-ion batteries. In the synthesis process, after graphene oxide and FeCl3 being mixed in aqueous media and subsequently being freeze-dried into the form of aerogel, FeCl3 reacts with epoxy groups on graphene oxide under N2 to from Fe3O4 nanoparticles and simultaneously reduce graphene oxide in the heat treatment, leaving behind a hierarchically porous graphene matrix on which Fe3O4 nanoparticles were uniformly dispersed. Such composite products, featured by its high porosity and homogeneous distribution of Fe3O4 nanoparticles, showed an enhancement in the electrochemical performance when used as anode materials in lithium-ion batteries. This work investigated the role of preparation parameters including the weight ratio of Fe3O4/graphene and heating temperature in affecting the electrochemical performance of as-prepared electrode. F1G2-600 presented a high reversible capacity of 1224 mAh/g at 0.1 A/g with the Coulombic efficiency of 73.8% in the first cycle. In the long-term test, F1G2-600 still delivered a remaining capacity of 573.8 mAh after 1000 cycles at 1 A/g with a retention rate of 82.8%. Therefore, this easily fabricated Fe3O4/graphene composite with high capacity and desirable durability holds promise in the scalable application as anode materials in high-power LIBs.

Capturing the Microstructural Complexities of PEMFC Catalyst Layers and Local Transports Therein Using Network Modeling Approach

The microstructural characteristics of the catalyst layer are critical for understanding the effect of local transport processes (water, reactant gas, and proton transport) in catalyst layers on overall PEMFC performance. Here, we present a network architecture that uses structured networks to capture the morphological heterogeneity of PEMFC catalyst layers. Using the poroelastic theory of swelling, it depicts how the ionomer within the catalyst layers absorbs water and expands in volume with respect to humidity which dictates the shift in porosity and pore size distribution of the catalyst layers. Local transport behavior (flooding, reactant gas, and proton starvation at the reaction sites) under different PEMFC operating conditions are analyzed by applying transport equations to the generated networks.

An Experimental Study on the Correlation between Characteristics of Gas Diffusion Layer and Performance Depending on Relative Humidity Variation in Proton Exchange Membrane Fuel Cell

As it is well known, Gas diffusion Layer(GDL) is a fundamental element to provide more efficient water transport in Proton Exchange Membrane Fuel Cell(PEMFC). Numerous previous studies showed how important and critical GDL is in PEMFC. There have been many efforts to improve the performance of GDL, such as studies on properties, structural improvement, and hydrophobic coating on substrate and micro porous layer. Through these efforts, PEMFC has been developed and also the relationship between GDL and each component was investigated well.Relative Humidity(RH) is an important factor that affects proton conductivity and mass transport and is also an factor to be considered for water management. Although it should be relatively clear, it is necessary to compare and verify between the numerical study and experimental study since they does not always matches.In this study, the results were compared with the physical properties of each GDL based on experimental data applying GDL with different characteristics. We studied to reveal the correlation between data such as thickness, porosity, and pore distribution of GDL and I-V Polarization curve conducted by changing RH conditions to investigate performance.

Relationship between Electrode’s Composition, Porosities and Performance on Mesoporous Pt/C Catalysts

The FCEVs have earned more attention in the past years, with the urge of finding green alternatives for fuel cells. Very convincing small series vehicles (such as the new Mirai) are spearheads for PEMFC technologies and shows how complex both the system and the MEAs have to be designed. More specifically, in the case of the MEA, the importance of mesoporous carbons as carbon support [1], enabling lower Pt poisoning, but also lower O2 resistance in the catalytic layer [2] has been clearly emphasized. In addition, the porosity distribution of the material was concluded to be both favourable to O2 transport, but also to ionomer film continuity onto the carbon support [2]. However, recent literature also indicated with DFT technologies that the solvent system used (hence the ink formulation) could have a major impact on the performance [3], with possible ionomer penetration in the pore, making sluggish performance with an important bottleneck to oxygen transport.In this study, we aim at demonstrating how solvents modify the interaction between the ionomer and the mesoporous carbon, with a systematic performance screening in PEMFC configuration (25 cm²), while changing ink formulation or parameters, linking the change of the pore distribution of the coated electrode (N2 adsorption), with the performances.[1] T. Yoshizumi, H. Kubo, M. Okumura, and T. Motor, SAE inernational, 1–6 (2021).[2] N. Ramaswamy, W. Gu, J. M. Ziegelbauer, and S. Kumaraguru, J. Electrochem. Soc., 167, 064515 (2020).[3] N. Kikkawa and R. Jinnouchi, J. Phys. Chem. C, 126, 11518–11528 (2022).

Numerical Study of Low-Temperature Ventilation Drying in a Wheat Grain Silo Considering Non-Uniform Porosity Distribution

The temperature and moisture content inside a grain pile are two important indicators for judging the safety of grain storage. To accurately predict the temperature and moisture content inside a grain pile, a numerical simulation was carried out of the drying process of a mesoscale wheat grain soil based on a thin-layer drying method, considering non-uniform porosity. The effectiveness of this method for wheat piles was verified through a comparison with the experimental data. The influence of different ventilation cage heights and ventilation temperatures on heat and moisture transfer in the wheat grain pile were also studied. The results show the following points. The numerical simulation method in this paper can effectively predict the temperature and moisture content of a wheat grain pile. The non-uniform porosity distribution model can better reproduce the state of ventilation during storage of wheat grain piles than the uniform porosity distribution model. The distribution patterns of flow lines in silos with different ventilation cage heights have certain similarities, but the high-speed airflow area will decrease as the height of the ventilation cage increases. Different ventilation temperatures will significantly affect the areas of high temperature and the rewetting inside a wheat grain pile.

Nonlinear in-plane buckling of fixed FGP-GPLRC arches subjected to a half-span distributed radial load

In this work, nonlinear in-plane buckling analysis of fixed functionally graded porous graphene nanoplatelet reinforced composite (FGP-GPLRC) shallow arches under a half-span distributed radial load is presented. Material properties of the arch with different porosity distribution modes are determined via a modified Halpin–Tsai micromechanical model. Neutral plane-based nonlinear governing equations of motion are established based on the principle of virtual work from which analytical solutions for the critical buckling load are derived and the complete equilibrium path is traced. Possible buckling modes of fixed FGP-GPLRC arches are determined by employing a perturbation technique. Key parameters controlling the buckling configuration switching are also proposed. FE analysis is then carried out to verify the accuracy of the presented solutions. Effects of porosity distributions, GPL weight fraction, and porosity coefficient on the buckling behaviors are comprehensively examined. It was found that under the action of a half-span distributed radial load, the fixed FGP-GPLRC shallow arches buckle in a limit point configuration only, and the equilibrium path especially the per-buckling branch is significantly affected by porosity coefficient.

Simulation of thermo-hydro-mechanical coupled heat extraction process of geothermal reservoir under varied geological conditions with CO2 as working fluid

The use of supercritical CO2 as a working fluid instead of H2O in an enhanced geothermal system (EGS) for extracting heat from hot dry rock geothermal resources has garnered significant attention. The objective of this study is to investigate how different geological conditions affect the heat extraction behavior of supercritical CO2 and to reveal the efficiency differences between supercritical CO2 and H2O as working fluids in each geological scenario, providing deeper insight into reservoir management. A series of 3D coupled thermo-hydro-mechanical models were established. Besides, the impact of initial temperature, pressure, porosity, permeability, and stress field on the heat extraction of EGS with different working fluids are also analyzed and compared. Results indicate that, at the same circulating volumetric flow rate, CO2-EGS generally exhibits an earlier thermal breakthrough time, lower net energy production, and reduced heat extraction rate compared to H2O-EGS. Taking into account the extended reservoir lifespan and the relatively small pressure difference between injector and producer in CO2-EGS, CO2 is a more suitable working fluid than H2O. Furthermore, the performance of CO2-EGS is primarily affected by the initial temperature, porosity, and permeability distribution pattern, rather than the initial pressure. On the one hand, a reservoir with low initial temperature, porosity and homogeneous permeability were found to be more conducive to enhancing the average net energy production. On the other hand, reservoir vertical permeability anisotropy can have a more profound impact on CO2-EGS efficiency compared to horizontal y permeability anisotropy. Additionally, this study also examined the impact of in situ stress field. It was found that, compared to H2O-EGS, both isotropic and anisotropic in situ stress fields have a weak effect on the performance of CO2-EGS, which can be attributed to the similarity of the channelization degree of the flow field under different stress conditions.