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Research on the THMC Coupling Model for Enhanced Geothermal Systems Based on the Framework of EDFM 29th

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Research on the THMC Coupling Model for Enhanced Geothermal ...

29th International Conference on Computational and Experimental engineering and Sciences, ICCES 2023

作者： Zhang, Weitao Han, Dongxu Jiao, Kaituo Chen, Yujie Yuan, Qing Gong, Liang Yu, Bo Qingdao266580 China Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil and Gas Development School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing102617 China State Key Laboratory of Multiphase Flow in Power Engineering School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an710049 China

ISBN: (纸本)9783031429866

The Enhanced Geothermal System (EGS) involves a complex thermo-hydro-mechanical-chemical (THMC) coupling process during long-term heat extraction. However, many models used to solve fractured reservoir problems are computationally time-consuming, especially when dealing with reservoir-scale engineering problems. To address this challenge, this paper proposes a novel THMC coupling model that solves the governing equations using a unified FVM framework based on the embedded discrete fracture model (EDFM). The accuracy of the model is confirmed by comparing the THC coupling and displacement (M) results with the Fully Resolved Solution Method (FRSM) from MRST software and COMSOL, respectively. Moreover, the model developed is utilized to simulate and analyze the spatiotemporal behavior of pressure, temperature, concentration, and mechanical deformation in EGS. The results suggest that the model is appropriate for effectively assessing the long-term production performance of EGS. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Finite volume method

Numerical study of specific C-shaped heat exchanger using porous medium and coarse mesh coupling method

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International Journal of Thermal Sciences 2025年 210卷

作者： He, Shaopeng Wang, Shiqi Wang, Mingjun Tian, W.X. Qiu, S.Z. Su, G.H. State Key Laboratory of Multiphase Flow in Power Engineering School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

Porous medium method is an effective simplified approach for the heat exchanger simulation when the numerous tubes and complex structures bring unacceptable computational resources to full-scale simulation. However, for the specific C-shaped heat exchanger, the tube side resistance and flow distribution characteristics that significantly affects the heat transfer and natural circulation performance cannot be obtained by the traditional porous medium method coupled with the one-dimensional node model for tube side. It is urgent to develop a new coupling method that can not only simplify modeling and calculation, but also obtain tube side high-resolution flow heat transfer characteristics. This study presents a novel calculation method which couples the porous medium mesh and the tube side coarse mesh. The coupling method was then applied to a typical C-shaped passive residual heat removal heat exchanger (PRHR HX), which is significant to the stable operation and the mitigation of accident conditions in the nuclear power plant. The coupling calculation method was validated against the full-scaled simulation and data from scaled-down experiment. The average relative error of heat transfer power is 2.1 % under steady state conditions. Under transient conditions, the average absolute error of the fluid temperature and wall temperature are less than 6 K. Then the 3D thermal-hydraulic characteristics of PRHR HX was studied. Owing to a greater gravitational pressure head, the mass flow rates in the extended tubes surpass those in the shorter tubes by a relative deviation of 27.4 %. The upper horizontal tube's heat exchange capacity constitutes approximately 70 % of the total power, leading to enhanced natural circulation. The outlet temperatures from various tubes tend to equalize. The boiling area gradually extended down along the heat transfer tubes. Our work would present an innovative calculation method to the numerical study and design optimization of the C-shaped heat

关键词： Nuclear power plants

Comparative analysis on gas–solid drag models in MFIX-DEM simulations of bubbling fluidized bed

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Chinese Journal of Chemical engineering 2023年第12期64卷 64-75页

作者： Ruiyu Li Xiaole Huang Yuhao Wu Lingxiao Dong Srdjan Beloševic Aleksandar Milicevic Ivan Tomanovic Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Shunde Institute of Inspection Guangdong Institute of Special Equipment Inspection and ResearchFoshan 528300China Department of Thermal Engineering and Energy "VINCA" Institute of Nuclear Sciences–National Institute of the Republic of SerbiaUniversity of BelgradeMike Petrovica Alasa 12-1411351 VincaPO Box 52211001 BelgradeSerbia

In this study,the open-source software MFIX-DEM simulations of a bubbling fluidized bed(BFB)are applied to assess nine drag models according to experimental and direct numerical simulation(DNS)*** influence of superficial gas velocity on gas–solid flow is also *** results show that according to the distribution of time-averaged particle axial velocity in y direction,except for Wen–Yu and Tenneti–Garg–Subramaniam(TGS),other drag models are consistent with the experimental and DNS *** the TGS drag model,the layer-by-layer movement of particles is observed,which indicates the particle velocity is not correctly *** time domain and frequency domain analysis results of pressure drop of each drag model are *** is recommended to use the drag model derived from DNS or fine grid computational fluid dynamics–discrete element method(CFD-DEM)data first for CFD-DEM *** the investigated BFB,the superficial gas velocity less than 0.9 m·s^(-1) should be adopted to obtain normal hydrodynamics.

关键词： MFIX-DEM Simulation Dense flow Gas-solid Bubbling fluidized bed Drag model

Improvement on Numerical Simulation of Supercritical Water flow in Horizontal Tubes: A Buoyancy-Tuned Turbulence Prandtl Number Model

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SSRN 2024年

作者： Hou, Zhenghui Guo, Xinyang Liang, Zhicheng Yang, Kuang Yang, Chaofan Wang, Haijun State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

To improve the predictive accuracy of numerical simulations for supercritical water, the effect of turbulence Prandtl number (Prt) on supercritical water heat transfer was extensively studied using the Shear-Stress Transport (SST) k-ω turbulence model. The efficacy of typical turbulence Prandtl number models for predicting heat transfer in horizontal tubes with supercritical water was evaluated based on wall temperatures measured experimentally and fluid temperatures obtained from multi-point temperature measurement devices. These models successfully demonstrated the phenomenon of thermal stratification due to physical property variations, but their predictive performance near the pseudocritical temperature, particularly in the top wall region, was not satisfying. Building upon this, a new turbulence Prandtl number model suitable for horizontal supercritical water tubes, named the SWBT model, was developed through constant calibration and the addition of buoyancy tuned. This model effectively replicates severe heat transfer deterioration (HTD) and buoyancy-induced improvements in heat transfer, showing robust predictive capabilities with a wide array of experimental data from both the authors and other researchers. The model was tested across ranges of P=24.5-26.5 MPa, q/G=0.11-0.67, and tube diameters of 7.5 mm, 26 mm and 43 mm. Additionally, the model's performance was benchmarked against experimental results of axially non-uniform heat flux conducted by the authors, successfully reproducing the variations in wall temperature due to changes in heat flux. This study substantially enhances the accuracy of numerical simulations for supercritical water in horizontal tubes, offering valuable insights for the engineering applications of supercritical water and the design of heat exchangers. © 2024, The Authors. All rights reserved.

关键词： Prandtl number

Effect of Fuel System on the Heat Releasing Method and flow-Path Design of Rocket-Based Combined Cycle Engine 14

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Effect of Fuel System on the Heat Releasing Method and Flow-...

14th International Conference on Mechanical and Aerospace engineering, ICMAE 2023

作者： Liu, Xiao Wang, Yinhu Yang, Yiyan Shi, Lei Yan, Dekun Xi'An Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an China Beijing Institute of Long March Vehicle Beijing China Northwestern Polytechnical University Science and Technology on Combustion Internal Flow and Thermal-structure Laboratory Xi'an China

ISBN: (纸本)9798350340327

Multi-components rocket-based combined cycle (RBCC) engine is widely applied in most two-stage-To-orbit program due to stable operation performance under variable flight conditions. Present researches numerically compared RBCC's performance under ramjet mode and scramjet mode, respectively, by using two fuel system, hydrogen and kerosene together with a \mathrm{k}-\omega SST turbulence model. Researches showed that the combustor area ratio should be increased to keep stable pressure difference balance between inflow and flame because of higher caloric value using hydrogen. Distributed heat addition method is benifit for overall performance improvement when using hydrogen. Different from using kerosene, head should be delayedly added in combustor downtream under scramjet mode. Moreover, the advanced heat addition amount should be decreased under ramjet mode to ensure effective isolator operation. © 2023 IEEE.

关键词： Hydrogen

Evaluation of Load Following Control Strategy for Heat Pipe-Cooled Microreactor Coupled with Closed Brayton Cycle System

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SSRN 2024年

作者： Qian, Yiran Liu, Tao Zhang, Yan Leng, Yuyang Shi, Tianrun Song, Meihui Chen, Weixiong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Heat pipe-cooled reactors (HPCRs), with their straightforward and compact design and inherent safety features, are considered a promising option for mobile nuclear power sources. However, the coupling between the HPCR and the energy conversion system complicates load tracking control. In this study, a comprehensive dynamic model of an HPCR coupled with a closed-air Brayton cycle (CABC) is developed. This model integrates a neutron kinetics point reactor model, a thermal resistance network model for the heat pipe, and a CABC model representing the power conversion system. To achieve effective load tracking, a control scheme for the Brayton cycle power is proposed, combining turbine bypass control with inventory control. The system’s response to load variations, from 100% full power (FP) to 50% FP at a rate of 5% FP/min, is analysed, considering reactor power self-regulation. The results indicate that the reactor power exhibits an overshoot of -4.36% and stabilizes after 2100s, while the fuel average temperature fluctuates within ±4.6°C and stabilizes at 2240s. Building on the dynamic performance of the HPCR-CABC system, a reactor power control scheme is developed by adjusting control drums to introduce external reactivity. This scheme successfully controls reactor power at a steady state within 720s, without fluctuation. However, the fuel average temperature fluctuates by more than 10°C, stabilizing after 9450s. To improve control effectiveness, a temperature correction channel is incorporated into the reactor power control system. As a result, the fuel average temperature fluctuates within ±0.3°C and stabilizes at the design value of 699.4°C within 860s. Compared to previous control schemes, the improved cascade reactor power control scheme results in a shorter stabilization time for the fuel average temperature. To assess the adaptability of the proposed HPCR-CABC coordination control strategy, simulations are conducted for load reductions from 100% FP to 80%, 60%,

关键词： Brayton cycle

Experimental Investigation of Pressure Pulsation and Noise Due to Thermodynamic Effects on Cavitation in High-Temperature Water

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SSRN 2024年

作者： Xu, Bo Hu, Hongfei Yang, Kuang Wang, Haijun State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

In power systems or equipment, water is often in a state of high temperature and high pressure. The thermodynamic effects are non-negligible during cavitation. The orifice plate, as one of the most fundamental structures in cavitation flow, is used as a research object in cavitation experiment to analyze the thermodynamic effects of high-temperature water. In this study, the variational mode decomposition is improved by using the center frequency and correlation coefficient of the intrinsic mode functions, thus developing an adaptive variational mode decomposition method (AVMD). This method effectively decomposes the pressure pulsations and radiated noise during cavitation and can reasonably classify different cavitation stages. The results indicate that periodic turbulence pulsation frequencies of 5-15 Hz are observed in non-cavitating regions. With the onset of cavitation, the flow field exhibits high-frequency pseudo-periodic frequencies, and the turbulence pulsation frequency gradually decreases, with Strouhal number (St) reducing from 0.2 to 0.1. In regions of severe cavitation, the St of turbulence pulsation frequency exceeds 0.4. Under the same cavitation number, during the development stage of cavitation, as the degree of subcooling decreases, the temperature drop in the cavitation region gradually increases, and the maximum is 2.5 K. The amplitude of pressure pulsations also declines, with the maximum reduction reaching 49.7%. In the severe cavitation stage, the temperature drop in the cavitation region reaches a maximum of 2.87K and is no longer affected by the degree of subcooling. The radiated noise sound pressure level exhibited similar trends as the pressure pulsations inside the pipe when the cavitation number changed. The noise was dominated by low frequencies, with a sound pressure level around 82dBA. The mid-frequency component had a sound pressure level around 79dBA, while the high-frequency component corresponded to a level around 77dBA. At the s

关键词： Variational mode decomposition

Research on Full-Day Operation Strategies of Virtual power Plants Integrating Interruptible Loads Energy Storage to Adapt to Various Weather Changes

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SSRN 2024年

作者： Chong, Daotong Tian, Zeyu Wang, Zhu Du, Guanghan Yan, Hui State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China

Interruptible load energy storage (ILES) represents a novel energy storage technology with the dual functionality of load and storage. The storage aspect of an ILES facilitates flexible and controllable scheduling. In contrast, the load attribute offers widespread energy storage potential. ILES surpasses traditional storage methods, particularly at large scales, by efficiently utilizing existing resources, reducing investment needs, and avoiding energy decay. However, the dual nature of ILES presents challenges in its direct application to power grids, necessitating its integration into virtual power plants (VPPs) as an indirect but crucial scheduling tool. This study develops a dynamic simulation model for a large-scale VPP incorporating an industrial-scale ILES. A control strategy is proposed, focusing on the efficient and flexible use of ILES and ensuring the VPP's safe, stable operation. This strategy includes a method for determining the dispatching time and range of the ILES and introduces three schemes—power universality, power enhancement, and power attenuation—to compute the dispatching power of the ILES and develop a dispatch plan tailored to varying needs. Additionally, the strategy enhances existing control systems by generating optimized signals to increase the dispatch rate and ensure operational safety. Simulation analysis of three typical scenarios assesses the dispatching parameters of the ILES, VPP operation safety, and system capacity for grid ancillary service participation. The findings show that while maintaining safety and stability, the ILES dispatch rate improved from 10 MW/min to 40 MW/min, diminishing energy losses and enhancing efficiency. Adjustments in dispatching times increased the ILES dispatching power from 53.7 MW to 101.8 MW and the VPP output power from 16.9 "MW∙h" to 96.7 "MW∙h", significantly boosting system flexibility and ancillary service capabilities. The variability in dispatching power, under scheme modifications, ranged

关键词： Energy storage

Thermal mechanical response analysis of the first wall in laser initial confinement fusion reactors

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International Journal of Advanced Nuclear Reactor Design and...

International Journal of Advanced Nuclear Reactor Design and Technology 2025年第2期7卷 147-155页

作者： Xinze Li Bingqian Zhang Chengcheng Tong Ronghua Chen Dalin Zhang Wenxi Tian Suizheng Qiu State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an 710049 China

This paper investigates the thermo-mechanical response characteristics of the first wall of a laser initial confinement fusion reactor under periodic transient heat flux loads. The first wall of the reactor experiences extremely high instantaneous heat loads during the target compression process, leading to temperature and thermal stress oscillations, which can cause material fatigue damage. Finite element analysis is employed to model the first wall under various chamber sizes and target energies, and the thermal-mechanical response characteristics of W, W/Cu functional gradient materials, and blanket materials are studied under thermal shock and cyclic loading conditions. The results indicate that W/Cu functional gradient materials can effectively alleviate thermal stresses on the first wall, especially in addressing the stress concentration at the interface. Fatigue life of the first wall is assessed using the Basquin model, and it is found that increasing the chamber size and increasing the target frequency can significantly reduce temperature oscillations and thermal stresses, thus extending the service life of the first wall. This study provides valuable design references for the optimization and design of the first wall in laser initial confinement fusion reactor.

关键词： Laser inertial confinement fusion reactor First wall Heat oscillation Thermal fatigue