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Transient Thermoelectric Characteristics of the Principle Prototype for the Heat Pipe Cooled Nuclear Silent Themoelectirc Reactor (Nuster)

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SSRN 2023年

作者： Guo, Kailun Zhang, Yin Lin, Xingyang Huang, Jinlu Wang, Chenglong Qiu, Suizheng Tian, Wenxi Su, Guanghui School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy And Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

This paper proposes an optimized design for the Heat Pipe ThermoElectric Generator(HPTEG) principle prototype. The refined scheme adopts high-temperature sodium heat pipes as heat transfer elements to enhance the overall operating temperature of the device. It adopts Half-Hessler(HH) alloy ThermoElectric Generator(TEG) arranged on the upper and lower sides of the heat exchanger to enhance the thermoelectric conversion efficiency of the device. A heat pipe dynamic conduction model is established to simulate the start-up process of the sodium heat pipe. A TEG model is developed, which is able to simulate the three-dimensional thermoelectric properties of the TEG. The numerical simulation platform is used to analyze the steady-state and transient thermoelectric properties of the refined HPTEG prototype. This study provides data support for the subsequent design modification of the future HPTEG principle prototype and provides ideas for the 3D transient calculations of the solid-state heat pipe reactors. © 2023, The Authors. All rights reserved.

关键词： Heat pipes

Thermodynamic Performance of Cacl2 Absorption Heat Pump Thermal Energy Storage System with Triple Storage Tanks

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SSRN 2023年

作者： Chen, Jinsen Zhou, Yuan Liu, Jiping Zhao, Yongliang Zhang, Shunqi Yan, Junjie MOE Key Laboratory of Thermal Fluid Science Engineering Xi'an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China

Absorption thermal energy storage has the characteristics of high thermal energy storage density (ESD) and low heat loss for long-term storage. To solve the coal-fired combined heat and power plant heat-power-coupling problem, in this work, an absorption heat pump thermal energy storage system (AHPTES) using CaCl2-water solution as the working fluid is proposed. A steady-state thermodynamic model of the system was constructed using Aspen Plus. Under the design conditions, the AHPTES system requires a tank volume of 464.61 m3 for one hour of operation, an ESD of 29.81 kW·h/m3, a thermal energy storage ratio of 46.50%, and a heating ratio of 53.54%. Compared to the dual-tank thermal energy storage system with H2O and CaCl2-water solutions as working fluids, the AHPTES system has 1.43 and 1.25 times higher ESD and 0.7 and 0.8 times lower tank volume, respectively. Then, the effects of CaCl2 mass fraction, driving pressure, evaporator outlet temperature, preheating temperature, and condensing temperature on the system performance are simulated. Improving the CaCl2 mass fraction, lowering the evaporator outlet temperature, and raising the condensing temperature and preheating temperature can boost the system's performance. At the optimal system performance, the required tank volume for one hour of system operation is 439.56m3, ESD can reach up to 37.39 kW·h/m3, heating ratio to 44.83%, and the energy storage ratio to 55.17%. Besides, raising the mass fraction of CaCl2 to 52% and decreasing the evaporator outlet temperature to 30 °C at 50% mass fraction resulted in crystallization of the system. © 2023, The Authors. All rights reserved.

关键词： Thermal energy

Thermal-Hydraulic Characteristics of Helical Cruciform Single Rod Based on Cfd Investigation

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SSRN 2023年

作者： Chen, Yiwen Zhang, Dalin Jiang, Dianqiang Wang, Xinan Tian, Wenxi Qiu, Suizheng Su, Guanghui 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’an710049 China

The helical cruciform fuel (HCF) takes advantages of strong mixing effects, self-supporting features, and strengthened heat transfer, potential to increase the fuel performance in nuclear reactors. In this work, hydraulic resistance and heat transfer characteristics of an HCF single rod cooled by water were studied based on CFD simulation. Various turbulent models were compared based on experimental data. The velocity field, transverse velocity, wall temperature, and fluid temperature distribution were obtained to discuss influences of geometric sizes on the fuel performance. After 3/8 of the pitch, flow was fully developed. The friction factor and surface heat transfer coefficient were higher with a shorter twist pitch owing to stronger mixing effect while they kept unchanged with variable cross-section sizes but a fixed equivalent diameter. Correlations of friction factor and surface heat transfer coefficient were proposed considering geometric modified coefficients based on a geometric dimensionless number, which were validated with new geometric cases. © 2023, The Authors. All rights reserved.

关键词： Heat transfer coefficients

Experimental Study on flow and Heat Transfer of Medium-Prandtl-Number Fluid Along a Hexagonal Helical Cruciform Seven-Rods

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SSRN 2023年

作者： Jiang, Dianqiang Zhang, Dalin Tian, Wenxi Qiu, Suizheng Su, Guanghui 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’an710049 China

A novel type of nuclear fuel named helical cruciform fuel may realize self-supporting for adjacent elements and improve heat transfer, both of which contribute to increasing the power density of the reactor. The flow and heat transfer characteristics of a hexagonal helical cruciform seven-rod bundle were experimentally investigated in the present work. 200 sets of isothermal frictional resistance experiments and 199 sets of heat transfer experiments were finished. The laminar flow region (200 © 2023, The Authors. All rights reserved.

关键词： Reynolds number

Atomic Insights into Hydrogen Peroxide Decomposition on the Surface of Pure and Pre-Treated Silver: A Reactive Molecular Dynamics Simulation Study

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SSRN 2023年

作者： Zhao, Xiao Feng, Yiming Zhang, Bowei Jin, Hui Wei, Xianggeng State Key Laboratory of Solid Propulsion Northwestern Polytechnical University Shaanxi Xi’an710072 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

Based on ReaxFF molecular dynamics simulation, H2O2 decomposition on pure and pre-treated silver catalyst is studied at a microscopic level. The pretreatment undergoes a surface annealing with redundant H2O2 on top of catalyst. The simulation results indicate that H2O2 decomposition can be drastically accelerated by elevating temperature. The extent of decomposition is closely related to bond, hydrogen bond, and potential energy of simulation system. It is found that H2O2 decomposition follows a four-stage HO-OH bond break mechanism while it needs three times longer for pre-treated silver catalyst than pure silver catalyst. The activation energy of pre-treated silver catalyst is about 50% lower than pure silver catalyst. However, the overall reaction rate of pre-treated silver catalyst is about an order of magnitude slower than pure silver catalyst, which owes to the much smaller pre-factor. It is believed that although the pretreatment causes silver oxide to be formed on the surface, it leads to more hydrogen and oxygen atoms deposited so that most active sites for catalytic reaction are blocked for further decomposition. This may be helpful to understand the inherent mechanism of H2O2 decomposition on silver-based catalyst and provide instructional advice for further catalyst modification design. © 2023, The Authors. All rights reserved.

关键词： Catalysts

Application and Optimization of Monte Carlo Method for Simulation of Light Propagation in Biological Tissue

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Zhongguo Jiguang/Chinese Journal of Lasers 2025年第9期52卷

作者： Zhang, Hao Liu, Yifeng Wu, Wenjuan Li, Dong Chen, Bin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

Objective The Monte Carlo (MC) method has become a cornerstone for simulation of light propagation in biological tissues, particularly for applications in laser therapy and medical imaging. However, traditional voxel-based Monte Carlo (VMC) methods often exhibit significant errors when dealing with complex curved surfaces due to the inherent limitations of structured grid discretization. By contrast, tetrahedron-based Monte Carlo (TMC) methods, based on unstructured meshes, offer better adaptability to complex geometries but incur higher computational cost. This study aims to address the trade-off between computational efficiency and accuracy in light propagation simulations by proposing a novel correction method to improve the performance of VMC in handling curved interfaces with large refractive index differences. The objective is to enhance the accuracy of VMC while maintaining its computational efficiency, making it more viable for practical biomedical applications, such as laser treatment and optical diagnosis. Methods This study compares the performance of VMC and TMC in light propagation simulations under different refractive index conditions. We propose a coordinate transformation-based correction method to reduce the errors in VMC caused by the inaccurate handling of reflection and refraction at curved interfaces. The simulations were carried out on a multi-layer skin tissue model with varying refractive index conditions;the laser light was directed at blood vessels embedded within the dermis. The correction method involves transforming the photon direction vector in a way that accounts for the curvature of the interface, thereby improving the accuracy of light photon interactions at the tissue boundaries. Simulations were conducted using MATLAB, and the results were validated through experimental cases, such as diabetic retinopathy laser treatment. The computational setup included an Intel i7-9700K processor and an NVIDIA GTX 3080 graphics card (GPU). Resu

关键词： Laser surgery

Investigation on the Parallel Computing Technique Using on the Numerical Simulation of Carbon Free Fuel

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Investigation on the Parallel Computing Technique Using on t...

Information Science, Parallel and Distributed Systems (ISPDS), International Conference on

作者： Weibin Wang Xutao Wei Department of Computer Science Xi'an Fanyi University Xi'an China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

The numerical simulation of the turbulent combustion is identified as one of the most promising methods on the designs of the combustion devices, for example: the internal combustion engine and gas turbine. This mainly depends on the development of parallel computing technique. However, the computational efficiency for different cases on different compute nodes and number of cores still needs to be studied. On the other hand, due to the requirements from the aim of peaking carbon dioxide emissions before 2030 and achieving carbon neutrality before 2060, modern energy system is requesting low carbon or carbon free fuels, such as ammonia (NH3). Therefore, the simulations of ammonia/air flame were performed in present investigation. The comparison between simulation cases on different compute nodes and number of cores illustrates that different cases requires different number of cores to achieve the best computational efficiency. The computational efficiency of each compute nodes are dissimilar, which can decrease the efficiency. Meanwhile, the methods in present study can predict the ammonia/air flames. The initial condition of velocity fluctuation is necessary for simulating turbulent flame. The wrinkles of the flames can be well predicted by the velocity fluctuation initial boundary condition.

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Development and Validation of Fully-Coupled Subchannel Analysis Code for Lmr within the Moose Framework

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SSRN 2023年

作者： Zhu, Xinyang Chen, Ronghua Wang, Jinshun Niu, Yuhang Wu, Yingwei Zhang, Dalin Tian, Wenxi Qiu, Suizheng Su, Guanghui School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

As one of the Gen IV advanced reactors, liquid metal reactor(LMR) holds promising prospects for its high fuel efficiency and excellent inherent safety performance. Owing to its complex working conditions and ultra-high operating temperature, a thermal-hydraulic analysis of the reactor core is gradually playing a bigger role in recent years. Therefore, a subchannel code FLARE for LMRs is developed within the MOOSE ***, a hybrid discretization approach involving DG and FEM as well as the JFNK method are employed to solve the equations in a fully-coupled way. To validate the computational accuracy and convergence of FLARE code, comparisons between the calculation values of FLARE, those of other programs and the experimental data are performed using 7-pin, 19-pin and 37-pin assembly experiments. The computational results indicate a good agreement between FLARE, experimental values, and other programs. In conclusion, FLARE code possesses the capability to accurately analyze LMR core. © 2023, The Authors. All rights reserved.

关键词： Reactor cores

Proposal design and thermodynamic analysis on a novel coal-based power generation system integrated with CO2 capture

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Proposal design and thermodynamic analysis on a novel coal-b...

Electrical engineering and Mechatronics Technology (ICEEMT), IEEE International Conference on

作者： Guobin Gao Ruiqi Mu Yali Yang Lei Yan Jun Gao Ming Liu Guoneng Jinjie Energy Co. Ltd Yulin China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

To enhance the energy efficiency and decrease the carbon emissions, a novel coal-based power generation system integrated with CO 2 capture is proposed in this study. The S-CO 2 cycle is integrated to recover the waster heat of system effectively. The heat transfer processes are well matched, and the irreversibility of heat exchangers in the system is reduced by splitting working medium appropriately. The system simulation and thermodynamic analysis models are developed. The energy and exergy efficiency of system are 51.32% and 50.07%, respectively. The system efficiency increases with the increase of the coal water slurry concentration (CWSC) and the decrease of the gasification temperature. When the CWSC is 35% and gasification temperature is 500 °C, the exergy efficiency of system reaches 51.74% and 50.59%, respectively.

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