3D Numerical Calculations Research Articles

Disaster mechanism of large-diameter shield tunnel segments under multi-source load coupling: A case study

The deflection squeezing of the shield shell and the eccentric jack thrust significantly impact the segment dislocation and damage. Based on summarizing the derivative relationship between engineering factors and disasters, this study established a 3D numerical calculation model under the multi-source load coupling. Then, this study explored the displacement and dislocation distribution of segments, as well as their derivative relationship with bolt failure. Furthermore, this study analyzed the spatial distribution and evolution characteristics of segment damage. Further revealing the disaster mechanism and proposing the engineering treatment measures. The research results indicate that as the deflection angle increases, the vertical relative compression deformation of the segment that is detaching from the shield tail (segment-DFST) becomes more significant. The plastic strain of the internal bolts inside the two segments in direct contact with the shield shell is mainly related to the radial and longitudinal dislocation. The increase in the deflection angle will lead to a more significant increase in the adjacent dislocation on both sides and the internal dislocation. The plastic strain of the internal bolts of the segment that is completely in the shield shell (segment-CSS) is more influenced by joint opening and longitudinal dislocation under the lower eccentric compression (LEC) state. The plastic strain of the internal bolts in segment-DFST is more influenced by radial dislocation and joint opening under the LEC state. The tension damage of the segments mainly occurs on both sides of the circumferential joint and the lower part of the segment-CSS. The compression damage of the segments is mainly distributed at the top and bottom of the segment-CSS. The eccentric distribution of jack thrust has the most significant impact on the block damage of the lower part of the segment-CSS. With the increase of the deflection angle, the compression damage and distribution range of the blocks at the bottom of the segment-DFST increase sharply. The compression damage and distribution range of the segment-CSS gradually spread from the upper and lower parts to the middle of the segment. The increase in deflection angle will promote the influence of the thrust in LEC state on the compression damage of the lower block of the segment-CSS, and on the tension damage of the upper block of the segment- DFST.

Design of photonic topological corner states for electrically pumped terahertz quantum cascade laser

Photonic topological corner states (PTCS) represent discrete zero modes whose frequencies stay in the topological bandgap and wavefunctions exhibit strong spatial localization, which is highly desirable for efficient surface-emitting lasers. While being extensively investigated in optically pumped lasers, the electrically pumped PTCS lasers are merely reported due to the lack of suitable configurations. In this paper, we propose a photonic cavity design based on the PTCSs that can be applied for electrically pumped terahertz quantum cascade lasers (QCLs). The cavity is constructed by following the canonical trivial-nontrivial domain, where the nontrivial domain with expanded and merged four QCL rods is surrounded by the trivial domain with shrunk and merged four QCL rods. Both domains follow the 2D Su–Schrieffer–Heeger (SSH) model. To further construct a fabrication-favorable 3D device, the designed QCL rod array is connected by 2D veins, which functionalize simultaneously as the intermedium for enhanced inter-/intra-cell coupling and the conductive connection to the device. The 3D numerical calculation is finally investigated.

Modelling the Influence of the Tube Support Plate on the Eddy Current Testing of the Steam Generator: Sensitivity Study & Validation

Eddy current testing (ECT) of Steam Generator (SG) tubes is part of the maintenance program of Nuclear Power Plants. Tube Support Plates (TSP) are usually only considered as extraneous signals for tube inspection. However, for long-term operation of SGs, there is a safety concern related to the build-up of deposits in the TSPs flow holes. The clogging-up of the TSPs flow holes affect the safe thermal-hydraulic operation of SGs. The deposits come from the feedwater train and are mostly iron oxides (magnetite) with a weak electrical conductivity and magnetite permeability.The ability of ECT probes to detect and characterize TSPs deposits is therefore of great interest. The most common and industrial ECT technique, the bobbin coil, averages the surrounding electromagnetic field over 360°, whereas the geometry of tri-foiled and quadri-foiled TSPs, and thus of clogging, is rather complex and non- axisymmetric, hence motivating the evaluation of the performance of conventional ECT rotating probes used for SGs tubes inspection. Although simulation is a powerful tool to support such a study, it requires dedicated models to be made available to NDT experts, and CEA develops ECT physical models in CIVA for this purpose. In addition to standard fast CIVA modules based on 3D semi-analytical or 2D numerical calculations restricted to canonical or axisymmetric parts, respectively, CEA develops a module dedicated to the simulation of SG tube inspection based on a 3D numerical simulation. This module allows tube deformation such as ovalization, bending or tube expansion. It also allows the addition of external objects such as anti-vibration bars, different geometries of tube support plates and now their clogging by deposits. This model is used to study various influent parameters and to perform benchmarks in the framework of a scientific collaboration between the CEA and the IRSN. Here, the specificity of the TSPs and their clogging justifies qualifying the simulation model before evaluating the influence of material and geometry properties of the deposit as well as the performance of the inspection techniques. We present the main features of the simulation module in CIVA, its experimental validation, and the main trends in the distortion of the simulated signal as a function of variation in the clogging description.

3D Stresses and Velocities Caused by Continental Plateaus: Scaling Analysis and Numerical Calculations With Application to the Tibetan Plateau

AbstractUnderstanding stresses is crucial for geodynamics since they govern rock deformation and metamorphic reactions. However, the magnitudes and distribution of crustal stresses are still uncertain. Here, we use a 3D numerical model in spherical coordinates to investigate stresses and velocities that result from lateral crustal thickness variations around continental plateaus like those observed for the Tibetan plateau. We do not consider any far‐field deformation so that the plateau deforms by horizontal dilatation and vertical thinning. We assume viscous creep, a simplified plateau geometry, and simplified viscosity and density distributions to couple the numerical results with a scaling analysis. Specifically, we study the impact of the viscosity ratio between crust and lithospheric mantle, a rectangular plateau corner, a stress‐dependent power‐law flow law and Earth's double curvature on the crustal stress field and horizontal velocities. Two orders of magnitude variation in crustal and lithospheric mantle viscosities change the maximum crustal differential stress only by a factor of ≈2. We derive simple analytical estimates for the crustal deviatoric stress and horizontal velocity which agree to first order with 3D numerical calculations. We apply these estimates to calculate the average crustal viscosity in the eastern Tibetan plateau as ≈1022 Pa · s. Furthermore, our results show that a corner strongly affects the stress distribution, particularly the shear stresses, while Earth's curvature has a minor impact on the stresses. We further discuss potential implications of our results to strike‐slip faulting and fast exhumation around the Tibetan plateau's syntaxes.

Simulation Method for Rubber Compounding under Isothermal Partial Filling Conditions

Rubber mixing is an important link in the production of rubber products. Computational fluid dynamics (CFD) simulation is often used to explore the effect of rubber mixing parameters on rubber mixing effect. Previous CFD-based rubber mixing simulation studies did not consider the impact of using 2D or 3D numerical calculation models on the numerical simulation results. In order to investigate the differences between 2D and 3D numerical computational models in rubber compounding CFD simulation problems, in this paper, we compare and analyze the results obtained from 2D and 3D computational models under different rotational speed conditions to investigate the differences between the models in the numerical simulation of rubber compounding. Three different experimental speeds of the rubber mixer—39, 44, and 49 r/min—were set during the study using 2D and 3D asynchronous rotor models with a speed ratio of 1.15, respectively. The rubber was processed using the Bird–Carreau model. The phase interface between rubber and air was calculated using the volume of fluid (VOF) method. The numerical simulation results of different models show that the rotational speed set to 49 r/min shows the best dispersion distribution effect; the mixing effect and speed change rule obtained by the 2D model are consistent with the results obtained by the 3D model. The performance of the results of the two models is consistent when exploring the numerical simulation of rubber compounding.

Modelling the Influence of the Tube Support Plate on the Eddy Current Testing of the Steam Generator: Numerical Tools and Experimental Validation

Eddy current testing (ECT) of Steam Generator (SG) tubes is part of the maintenance program of Nuclear Power Plants. Tube Support Plates (TSP) are usually only considered as extraneous signals for tube inspection. However, for long-term operation of SGs, there is a safety concern related to the build-up of deposits in the TSPs flow holes. The clogging-up of the TSPs flow holes affect the safe thermal-hydraulic operation of SGs. The deposits come from the feedwater train and are mostly iron oxides (magnetite) with a weak electrical conductivity and magnetic permeability. The ability of ECT probes to detect and characterize TSPs deposits is therefore of great interest. The most common and industrial ECT technique, the bobbin coil, averages the surrounding electromagnetic field over 360°, whereas the geometry of tri-foiled and quadri-foiled TSPs, and thus of clogging, is rather complex and non-axisymmetric, hence motivating the evaluation of the performance of conventional ECT rotating probes used for SGs tubes inspection. Although simulation is a powerful tool to support such a study, it requires dedicated models to be made available to NDT experts, and CEA develops ECT physical models in CIVA for this purpose. In addition to standard fast CIVA modules based on 3D semi-analytical or 2D numerical calculations restricted to canonical or axisymmetric parts, respectively, CEA develops a module dedicated to the simulation of SG tube inspection based on a 3D numerical simulation. This module allows tube deformation such as ovalization, bending or tube expansion. It also allows the addition of external objects such as anti-vibration bars, different geometries of tube support plates and now their clogging by deposits. This model is used to study various influent parameters and to perform benchmarks in the framework of a scientific collaboration between the CEA and the IRSN, related for example to the inspection of the U-bend tubes or of a friction wear under the anti-vibration bars. Here, the specificity of the TSPs and their clogging justifies further investigations between CEA and IRSN to qualify the simulation model before evaluating the influence of material and geometry properties of the deposit as well as the performance of the inspection techniques. We present the main characteristics of the simulation module in CIVA.

Study of Coherent Smith–Purcell Radiation in the Terahertz Region Using Ultra-Short Electron Bunches

Smith–Purcell radiation (SPR) can be generated nondestructively, providing valuable applications in light sources and beam monitors. Coherent SPR is expected to enable single-shot measurements of very short bunch lengths on the fs scale. Since the reconstruction of the longitudinal bunch shape from the coherent SPR is based on the reliable SPR spectrum, a more detailed understanding of the properties of the radiation is important in this context. Employing a 100 fs ultrashort electron bunch at the t-ACTS test accelerator, the spectrum, angular distribution, and polarization of the produced coherent SPR were measured in the terahertz frequency region and compared with a model calculation. In addition to the widely known surface current model evaluation, the effect of the geometrical shading effect on induced currents on metal surfaces was evaluated using 3D numerical calculations. The obtained SPR characteristics are also presented. In the evaluation of the grating with a shallow blaze angle, it was found that the shading effect has a non-negligible effect on the generated SPR intensity; the measured angular distribution and polarization results were in good agreement with this result.

Synergistic optimization of partition water distribution, non-equidistant fillings and dry-wet hybrid rain zone for wet cooling towers

Existing single-zone or two-zone synergistic optimization technologies have limited performance improvements for the large natural draft wet cooling towers (LNDWCTs). To further improve the cooling performance of the LNDWCTs, this study proposes for the first time a three-zone (water-spraying, fillings and rain zones) synergistic optimization method from a global optimization perspective. The 3D numerical calculation model is created and validated. Then, this work investigates emphatically the impact of the different three-zone parameters on the cooling performance, including the partition water distribution radius (R1 = 20 ∼ 60 m), the water distribution percentage in the inner zone (γ=5 ∼ 90 %), the fillings partition radius (R2 = 0 ∼ 65 m), the total coverage area of the split-flow plate (S = 2000 ∼ 2900 m2), the installation angle (θ=0 ∼ 27°), the split-flow plate length (L = 15 ∼ 55 m) and number (n = 3 ∼ 10). The simulation results illustrate that, within the studied range, the water temperature drop, cooling efficiency and Merkel number increase and then decrease with the increasing R1,γ, R2, θ and n, and increase successively with the increasing S and L. The optimized three-zone parameter combination scheme is R1 = 55 m, γ=75 %, R2 = 50 m, S = 2900 m2, θ=6°, L = 55 m and n = 7. Compared to the LNDWCT without any optimization technology, the water temperature drop, cooling efficiency, Merkel number, ventilation and evaporation loss of the cooling tower with optimized three-zone synergistic pattern increase by 0.58 °C, 3.37 %, 0.17, 1480 kg/s and 41.28 kg/s, respectively. This study can lay a theoretical basis for the multi-zone synergistic optimization research of LNDWCTs and provide a reference for the technical modifications and engineering applications.

Optimized designing of generalized electrodes for aluminum/steel resistance spot welding process based on numerical calculation

This work focused on the effects of using different electrode combinations on the welding process and welding quality during aluminum/steel resistance spot welding (RSW) process. The electrodes used during the RSW process can be classified into two catalogues, planar type (P type) and sphere type(S type). An effective two dimensional (2D) numerical calculation model using finite element method (FEM) was developed. In the model, the friction effects between different contact surfaces were seriously considered, and the accuracy and reliability of the model were verified by means of actual welding experiments. Subsequently, the numerical calculation model was used to determine which type of electrode combination was the best one for welding quality by analyzing corresponding RSW processes using four different electrode combination schemes: PP type, SS type, PS type and SP type for upper and lower electrodes. To guarantee scientific nature of the comparisons and analyses, a constant energy regulation method was introduced for each process. The heat energy generation analyses, intermetallic compound formation and growth analyses, and current density analyses were conducted. Combining with actual experiments, the results showed that the welded joint obtained from RSW process using SP type electrode combination scheme had the best comprehensive performance, not only in the double nugget sizes, but also in the deformations of two types of parent metal sheets. In addition, the optimum sizes of the electrodes in this combination were determined through numerical calculations and experiments. Final result showed that the optimum diameter for S type and P type were respectively 9 mm and 60 mm. The work can supply important references for the dissimilar metal RSW process improvement.

Physical and numerical investigation on nonlinear mechanical properties of deep-buried rock tunnel excavation unloading under complicated ground stresses

The nonlinear stress and deformation response of tunnel excavation unloading under high and complicated geostresses are important features of deep rock tunnel engineering, and such conditions differ significantly from those of shallow tunnels. Additionally, several studies on deep tunnels have focused on mechanical behaviors of rock tunnels at certain depths, ignoring nonlinear responses of rock tunnels at various depths. In this study, physical model tests and three-dimensional (3D) numerical calculations concerning complicated ground stresses were conducted to investigate the nonlinear mechanical and strength properties of tunnels excavated in rock formations with varying buried depths. The generalized Zhang–Zhu criterion (GZZ) was found to appropriately describe the nonlinear laws of rock strength (yield) with stress levels on the π plane, and the correctness and reliability of the GZZ strength criterion were subsequently verified by comparing the deformation monitoring data of physical model testing with different strength criteria-based numerical results. These results were then used to examine the stress distributions, deformations, and failure characteristics of physical model tunnels under complicated stress conditions at various buried depths. The nonlinearity of stress and deformation of the model tunnels are directly related to stress conditions, especially to the horizontal tectonic stress. This indicates that the traditional linear design approaches and practical experiences related to shallow tunnels dominated by gravity stress are not applicable to deep-buried tunnels under high and complicated ground stress conditions.

Numerical investigations of biomass pyrolysis with partial oxidation in a drop tube reactor

This study relates to 2D numerical calculations of fast pyrolysis with partial oxidation of pine and pine bark in a drop-tube reactor at 550 °C. Numerical studies were supported by experiments using thermogravimetric analysis of pine, pine bark, and pure lignin. The study involved 3 atm of pyrolysis: pure nitrogen, 95% nitrogen/5% oxygen, and 90% nitrogen/10% oxygen v/v. Numerical calculations were performed using Euler–Lagrange multiphase theory. According to the results, it was possible to linearly reduce the amount of char from 49% to 34% for pine and from 57% to 36% for pine bark, as the oxygen content in the carrier gas increased from 0 to 10% v/v. Furthermore, the addition of oxygen decreased the required energy for pyrolysis from 1.55 to 1.1 MJ/kg for pine and from 1.6 to 1.1 MJ/kg for pine bark at the maximum considered oxygen content. Simultaneously, owing to the increasing oxygen content in the carrier gas, gaseous products were promoted, and the mass ratio of CO to CO2 was almost the same for all cases and was approximately 0.6.

Design of an External Centrifugal Fan for the Cooling System of an Electrical Machine

Air cooling systems for electrical machines still do not lose their relevance. Especially noteworthy here is the aviation industry, in which special attention is paid to the weight and size of all systems, as well as the high density of equipment layout, which can interfere with the implementation of other types of cooling. At such times, only air cooling can be used to ensure the optimum operating temperature of the electrical machine. This article presents a research work on the profiling of blades for an external centrifugal fan of the air-cooling system of an electrical machine. The study is based on 3D numerical calculations using computational fluid dynamics software. Based on the results obtained, a design option was chosen that provides maximum performance.

Study on the simplified model of vertical double U-pipe ground heat exchanger

A simplified semi-analytical model of vertical double U-pipe ground heat exchanger was established. The validity of the established model is examined by contrasting the figured outcomes with experiment data, emulation results of 3-D numerical model and calculation results of infinite line-source model for different inlet boundary conditions and configurations. After one hour, the semi-analytical model?s relative error is less than 0.32% under the boundary condition of given inlet fluid temperature. Under the boundary condition of given total heat input rate, the semi-analytical model?s relative error after ten hours is less than 0.11%, while the infinite line-source model?s relative error is less than 0.60%. The semi-analytical model is in good agreement with experiment and numerical model, and has higher calculation accuracy than infinite line-source model.

A Method to Study the Influence of the Pesticide Load on the Detailed Distribution Law of Downwash for Multi-Rotor UAV

Multi-rotor plant protection Unmanned Aerial Vehicles (UAVs) have suitable terrain adaptability and efficient ultra-low altitude spraying capacity, which is a significant development direction in efficient plant protection equipment. The interaction mechanisms of the wind field, droplet, and crop are unclear, and have become the bottleneck factor restricting the improvement of the deposition quality. This paper suggests a method to study the influence of the pesticide load on the detailed distribution law of downwash for a six-rotor UAV. Based on a hexahedral structured mesh, a 3D numerical calculation model was established. Analysis showed that the relative errors between the simulated and measured velocities in the z-axis were less than 11% when the downwash air flow was stable. Numerical simulations were carried out for downwash in hover under 0, 1, 2, 3, 4, and 5 kg loads. The effect of load on the airflow was evident, and the greater the load was, the higher the wind speed of downwash would be. Then, the influence of wing interference on the distribution of airflow would be more pronounced. Furthermore, under the rotation of the rotor and the extrusion of external atmospheric pressure, the “trumpet” phenomenon appeared in the downwash airflow area. As an extension, the phenomenon of the “shrinkage–expansion” was shown in the longitudinal section under heavy load, while the phenomenon of “shrinkage–expansion–shrinkage” was present under light load. After that, based on the detailed analysis of the downwash wind field, the spray height of this multi-rotor UAV was suggested to be 2.5 m or higher, and the nozzle was recommended to be mounted directly under the rotor and to have the same rotation direction as the rotor. The research in this paper lays a solid foundation for the proposal of the three-zone overlapping matching theory of wind field, droplet settlement, and canopy shaking.

A benchmark problem for the verification of numerical calculation methods considering magnetic hysteresis

Previously, 36 TEAM benchmark problems have been established, used to verify the numerical calculation methods of electromagnetic fields. Among them, there is only one problem related to the magnetic field considering magnetic hysteresis, which is problem 32. The results of it are obtained by experimental measurement. In this paper, a same kind of benchmark problem is proposed, in which the field results are obtained by using analytical method. This benchmark problem can be used to verify both 2D and 3D numerical calculation methods. The analytical solving process of the problem is that H is obtained by using Ampere’s law, then B is calculated based on the hysteresis model of the material, so that the field distribution results are formed. The required hysteresis model could be any kind, such as Preisach model, J–A model, etc. As long as the same kind of model is used both in the benchmark problem and in the numerical method, the numerical method can be verified through the proposed benchmark problem. Considering the form of J–A hysteresis model required by the benchmark problem does not exist, which is the field separation-based forward dynamic J–A model, it is derived based on the forward static J–A model.

An Intelligent Optimization Back-Analysis Method for Geomechanical Parameters in Underground Engineering

The geomechanical parameters in underground engineering are usually difficult to determine, which can pose great obstacles in underground engineering. A novel displacement back-analysis method is proposed to determine the geomechanical parameters in underground engineering. In this method, the problem of geomechanical parameter determination is converted into an optimization problem, regarding the geomechanical parameters as the optimization parameters, and the error between the calculated results and the field measurement information as the optimization objective function. The grasshopper optimization algorithm (GOA), which offers excellent global optimization performance, and the Gaussian process regression (GPR) machine learning, offering powerful fitting ability, are combined to address the time-consuming numerical calculations. Furthermore, the proposed method is combined with the 3D numerical calculation software FLAC3D to form the GOA-GPR-FLAC3D method, which can be used in the displacement back-analysis of geomechanical parameters in underground engineering. The results of a case study show that the proposed method can greatly improve computational efficiency while ensuring high precision compared with the GOA. When applied to the Tai’an Pumped Storage Power Station, this method can obtain more accurate results compared with the GOA under the same evaluation times and is more suitable for the back-analysis of rock parameters in underground engineering.

Experimental and numerical investigations on damage assessment of high-density polyethylene pipe subjected to blast loads

Buried high-density polyethylene (HDPE) pipelines have been extremely vulnerable to terrorist attacks and third-party damage in recent years, so it is important to study the vibration response and safety criterion of buried HDPE pipelines under the action of surface blast loads. In this paper, based on the full-scale field tests, the damage characteristics of HDPE pipes under the action of surface blast loads are studied. Next, a 3D numerical calculation model was established to analyze the response characteristics of the buried pipes subjected to surface blast loads and its reliability was verified using the field monitoring data. Then, the safety of the pipes under different blast load conditions was studied in combination with numerical simulation software, and different damage models of the pipe were established based on damage theory. The results show that the peak particle velocity (PPV) of both the pipe and the surface increases as the distance from the explosive decreases, and the vibration velocity of all measurement points is dominated by the vertical direction (Y). Meanwhile, as the surface explosive is triggered, the pipe is prone to overall bending deformation in the axial direction, resulting in the destruction of the pipe. Finally, based on the comprehensive numerical calculations, numerical simulation results were obtained for different damage levels of the pipes under surface blast loading. What’s more, the damage prediction model of the pipes is also proposed, and the critical curves corresponding to different damage levels are derived.

Numerical analysis of weld bead formation process in the dissimilar material fiber laser welding

The weld bead formation process is closely related to welding materials because of the thermophysical properties involved. In this paper, a 3D numerical calculation model to explore the weld bead formation process in fiber laser welding of dissimilar materials is presented. The formed welded joint during the fiber laser welding of dissimilar materials shows characteristics that are different from that during the welding of the same material. The differences in the thermophysical properties between the materials are taken into consideration in the developed model. By means of comparison with the laser welding of the same material, the corresponding formation characteristics of a dissimilar weld bead are analyzed in terms of temperature distribution, molten metal flow, and thermophysical properties based on numerical simulation results. Due to the differences in the thermophysical properties, the weld bead, the temperature field, and the flow field are asymmetric in the laser welding of dissimilar materials. The moving processes of the two sides of the molten pool are extracted and discussed. The influence of an asymmetrical flow field on both sides of the molten pool is the critical factor accounting for the generation of asymmetric behaviors in the dissimilar material fiber laser welding. The proposed method in this paper can be utilized to provide guidance for revealing the weld formation process in dissimilar laser welding and to obtain weldment with high quality in practical welding.

CFD simulation of the impact of tip clearance on the hydrothermal performance and entropy generation of a water-cooled pin-fin heat sink

In this paper, the 3D numerical calculations of the water flow inside a pin-fin heat sink (PFHS) to determine the influence of tip clearance on the hydrothermal behavior and frictional & thermal irreversibilities of the fluid flow. The numerical simulations were conducted for five different fin heights (ξ = 1.5 mm to 2.5 mm) considering four different Reynolds numbers (Re=500, 1000, 1500, and 2000). The results demonstrated that the highest heat transfer coefficient is associated with ξ = 2.25 mm due to more uniform vorticity distributions, while the minimum central processing unit (CPU) average temperature is obtained for ξ = 2.5 mm due to the higher heat transfer surface area. The minimum thermal and frictional entropy generation rates are associated with PFHS with ξ = 1.5 mm. However, the PFHS with ξ = 2.25 mm has the highest Performance Evaluation Criterion (PEC) of nearly equal to 1.28 as compared to the other ξs. Besides, the fluid flow from the pin-fin base to the top and vice versa leads to create the vortices especially at the entrance of the PFHSs with tip clearance.

Numerical Study of Temperature Profiles of Transient Flow in the Geothermal Oilfield

Some petroleum wells that are no longer productive still have heat in their formation rocks. Those heat can be extracted and utilized by injecting working fluid into the wellbore. The current study’s objective was to create a 2D numerical calculation program for transient flow temperatures inside the well then it was used to calculate the temperature distribution in oil and gas fields in the Arun field and BK Area. The injected fluids were modeled as a double-pipe heat exchanger. Heat transfer processes inside the wellbore were convection in the inner pipe and the annulus and conduction in the pipe walls and rock formations. The computational calculation used a finite difference method. The computation results were then compared with calculations from the literature. After being validated, the program was used to calculate the Arun field and BK Area temperature distributions. This study found that compared with the reference literature, the current results had a similar optimum temperature range of 130°C-160°C but had different profiles shape with an average deviation of 12%. In the Arun fields, simulation results indicated that the field could reach temperatures between 90°C-120°C and was classified as a medium-temperature geothermal source. BK Area could reach optimum temperatures between 50°C-80°C and be classified as the low-temperature geothermal.