This study investigates the heat transfer characteristics of the water-cooled wall in a supercritical once-through boiler under low-load in deep peak-shaving. Conventional heat transfer correlations are developed from steady-state experimental data and often fail to accurately predict wall-temperature evolution under rapid variations, leading to significant deviations during transient processes. To address this issue, a 20° inclined straight tube was selected as the test section based on the structural of the water-cooled wall in supercritical boiler. The experimental ranges were P = 6-19 MPa, mass flux at G = 200-1600 kg m−2·s−1, and heat flux at q = 0-350 kW m−2. The effects of heat flux, pressure, and mass flux on steady-state heat transfer characteristics were first clarified, and the applicability of conventional heat transfer correlations under transient conditions was then evaluated. The results show that conventional steady-state correlations can reproduce the overall trend of wall-temperature variation, but fail to capture the local transient response during rapid mass-flux changes. Based on the experimental results, an empirical model was developed by introducing a history-dependent correction to the quasi-steady heat-transfer correlation. The correction represents the combined the effects of wall thermal storage, fluid-side relaxation, and transient heat-flux redistribution. The proposed model predicts wall temperature during transient processes with an error of less than 3%. After further optimization by incorporating a Reynolds-number-dependent response time, the predicted convective heat transfer coefficients are mainly distributed within the error band of −5% to +18%. The model predicts 2591 apparent-HTC data points with a MAPE of 3.81%, while all relative errors fall within −12% to +21%. The proposed model provides an effective method for transient wall-temperature prediction and offers useful support for the thermal safety assessment and flexible operation of supercritical once-through boilers under low-load conditions.

T-junctions are widely used in nuclear reactor piping to merge and redistribute flows. Frequent mixing of non-isothermal fluid within these fittings leads to thermal fatigue in the piping system. Liquid metal cooled fast reactors (LFRs) have developed rapidly and are attracting growing international attention, owing to their prospective advantages for Generation-IV nuclear systems and potential roles in future fusion-energy applications. This study employs large-eddy simulation (LES) to analyze the temperature and velocity fields of non-isothermal LBE mixing in the T-junction under various momentum ratios (M-R), revealing the vortex-structure evolution and near-wall thermal-pulsation mechanisms in the main pipe for three typical flow regimes (impinging jet, deflected jet and wall jet). Compared to the wall jet case (M-R= 4.51), the impinging jet case (M-R= 0.25) exhibits an approximately 11.3% higher dimensionless radial RMS temperature peak, with its peak location shifting from y/r(m)= 0.175 to y/r(m)=-0.685. In all three regimes, maximum circumferential near-wall temperature fluctuations at 1D(m) section occur at theta=+/- 65 degrees similar to +/- 75 degrees A deeper mixing-mechanism analysis of the impinging jet shows that vortices shed from the leading edges of the main and branch pipes at the same frequency, propagate downstream along the main-branch interface, and induce vigorous mixing. As the measurement section moves downstream from 0.5D(m) to 4D(m) from the branch inlet, the dimensionless RMS temperature peak gradually decreases and the region of strongest pulsation shifts from the upper to the lower portion of the pipe. Across all sections, the dominant near-wall temperature-fluctuation frequency band lies between 1.4 and 1.8 Hz. The findings will serve as a reference for the thermal-hydraulic design of future liquid-metal-cooled fast reactors.

This study proposes a proton exchange membrane fuel cell (PEMFC) waste-heat cascade utilization system considering the thermal management of a metal hydride hydrogen storage tank (MHT), aiming to improve the utilization efficiency of PEMFC waste heat while supporting integrated hydrogen supply. To address the mismatch in temperature level and heat flux between the PEMFC and the MHT, a thermoelectric generator (TEG) is introduced to establish a thermal coupling pathway. Through this coupling, the waste heat from the PEMFC is redistributed. Specifically, part of the heat is stably utilized to drive the endothermic hydrogen desorption process of the MHT via TEG coupling, while the remaining heat is directed to an organic Rankine cycle (ORC) for thermoelectric conversion. A coupled thermodynamic and exergy analysis model-including the PEMFC, ORC, TEG, and MHT-was established to evaluate the effects of current density, stack temperature, PEMFC cooling-water temperature difference, and MHT inlet cooling-water temperature. The results show that current density is the dominant factor influencing MHT desorption behavior, determining the desorption rate, duration, and heat demand; moderate increases in current density and stack temperature improve the power outputs of both the ORC and the TEG. Under typical operating conditions, the proposed system increases exergy efficiency by about 10% compared with a standalone PEMFC, achieving a maximum efficiency of 56.94%. These findings indicate that the system can not only effectively recover waste heat but also provide a stable heat source for MHT hydrogen desorption, offering valuable insights for the development of integrated PEMFC-metal hydride energy systems.

T-junctions are widely used in thermal engineering systems, energy systems, and chemical process connection. Non-isothermal mixing of hot and cold fluids within these fittings can readily induce thermal stratification and thermal fluctuations, thereby affecting structural safety during operation. In this study, a combined experimental and large eddy simulation (LES) approach was employed to investigate the mixing characteristics of non-isothermal water in vertical T-junctions under different momentum ratios (MR). The results show that, as the MR increases, the hot-cold fluid interface as well as the high-value region of temperature fluctuations shift upward as a whole. As the MR decreases, the impingement and squeezing effects of the branch jet on the main flow become stronger. At MR= 0.58, the dimensionless time-averaged velocity peak is approximately 35.7% higher than that in the MR= 3.77, while the dimensionless root mean square (RMS) velocity peak is approximately 41% higher. The LES results agree well with the experimental data, with the overall relative error being less than 10%. Under downward branch injection, the hot-cold fluid interface gradually migrates from the lower part of the main pipe toward the upper wall as the MR increases, while the spatial extent of the high vorticity region gradually decreases and changes from large scale interfacial disturbance to localized near-wall disturbance. At the X = 1Dm section, the peak dimensionless time-averaged temperature shifts from 0.737 (y/rm=−0.48) in the MR= 0.28 case to 0.927 (y/rm=0.343) in the MR= 3.77 case, while the peak dimensionless RMS temperature shifts from 0.314 (y/rm=−0.772) to 0.394 (y/rm=0.077). Under the same MR, downward branch injection more readily forms a locally concentrated high temperature region and a higher peak temperature fluctuation, whereas upward branch injection more readily produces a broader high temperature region and a wider high amplitude temperature fluctuation zone. The corresponding dominant frequency ranges are 5.2–5.9 Hz versus 3.2–4.0 Hz, 3.6–4.1 Hz versus 2.6–3.0 Hz, and 2.2–2.5 Hz versus 1.4–1.8 Hz, respectively. The present results can provide a reference for mechanistic analysis of non-isothermal mixing in vertical T-junctions and for the thermal safety design of complex piping structures in related thermal engineering systems.

In the pursuit of higher heat transfer efficiency of microchannel heat exchangers in Supercritical carbon dioxide (sCO(2)) Brayton cycle power generation system, the structure of microchannels is becoming increasingly complex. However, limited by the applicability of existing techniques such as chemical etching and diffusion bonding, these structures are difficult to manufacture. 3D printing manufacturing technology offers a significant promise for fabricating micro-scale and complex-structured channels. Unfortunately, the overall performance in 3D printed channels is still not quantitatively evaluated. In this study, straight circular channels fabricated using 3D printed SLM technology with an outer diameter of 6 mm and an inner diameter of 2 mm were fabricated. A systematic experimental study was conducted with a supercritical carbon dioxide flow and heat transfer test platform. Another straight channel made by conventional machining was tested and compared. It was found that the frictional and heat transfer coefficients in 3D printed is much higher than that in conventional machining channel, which is mainly effect by its large roughness height. In the liquid-like region, the Performance Evaluation Criterion (PEC) for 3D printed channel ranged from 1.67 to 2.52; in the pseudocritical region, the PEC ranged from 2.39 to 2.53; and in the gas-like region, the PEC ranged from 1.60 to 2.18. Based on the experimental data obtained, a new heat transfer predictive correlation for 3D printed channels on supercritical carbon dioxide was established. The deviation between predicted value and experiment data is within +/- 20 % band.

With the swift advancement of renewable energy sources, notably solar and wind power, there is an escalating demand for conventional thermal power units to perform deep peaking-shaving and valley-filling operations. Gaining a comprehensive understanding of the dynamic response during the deep peaking process is essential for ensuring the operational safety of thermal power units. This research offers an extensive experimental investigation into the dynamic response of supercritical fluids to step input across a broad temperature range, with a particular emphasis on their behavior under supercritical pressures exceeding 22.074 MPa. By examining the dynamic behaviors across both the time and frequency domains, this study unveils pivotal insights into the system's response characteristics, which are crucial for optimizing the performance and reliability of thermal system. The investigation uncovers that the dynamic behavior of the heating flow system is sensitive to the bulk temperature. In liquid-like conditions (T/T-pc<0.95), the system rapidly achieves a new equilibrium state, indicative of a first-order response. Conversely, as the bulk fluid temperature escalates, the response duration extends, demanding more time to reach stability and potentially manifesting as zero-damping periodic oscillations in the vapor-like phase (T/T-pc >1.05), necessitating the application of higher-order functions for accurate modeling. The temperature response to step input is observed to be markedly different across various temperature regions. The transfer function analysis indicates that in the liquid-like region, the system behaves akin to a first-order function with a gradually increasing time constant to a new steady state, characterized by a damping ratio greater than one (zeta > 1). However, in the vicinity of the pseudocritical region, the time constant exhibits a nonlinear and rapid increase, with a corresponding rise in the damping ratio, complicating the system's approach to a new steady state (1>zeta > 0). This is accompanied by an amplified amplitude of fluctuations. In the vapor-like region, the emergence of periodic oscillations with zero damping (zeta = 0) is noted, which can be effectively captured by a fourth-order transfer function. With the proposal of transfer functions for different operational regions, providing a valuable tool for predicting dynamic responses in complex flow systems. These findings contribute to a deeper understanding of supercritical fluid dynamics and have implications for the design and operation of systems subjected to supercritical conditions.

Transpiration cooling is a promising thermal protection technology for hypersonic vehicles, yet its coupled two-phase heat transfer mechanisms in porous media require deeper understanding. This study develops a 1D numerical model using the local thermal non-equilibrium two-phase mixture model (LTNE-TPMM) to evaluate how porous-medium properties and operating conditions impact cooling performance. Key findings indicate that higher solid thermal conductivity lowers wall temperatures, while increased porosity and particle diameter reduce pressure drop but intensify thermal non-equilibrium. Additionally, an inlet thermal diffusion effect was identified, in which backward heat conduction through the porous solid skeleton causes thermal dissipation near the inlet, leading to lower-than-expected outlet fluid temperatures. To quantify this phenomenon, a modified porous-medium Peclet number Pep is proposed. Results show that a lower Pep strongly correlates with enhanced inlet thermal diffusion. Within the investigated parameter range, these results provide preliminary guidance for the analysis and early-stage design of transpiration cooling systems.

Refrigerant-induced noise near the electric expansion valve (EEV) is a critical concern for automotive acoustic comfort, yet its underlying mechanisms remain poorly understood due to limited experimental accessibility. This study presents a numerical investigation of flow-induced noise in EEVs under both single-phase and two-phase inflow conditions using an integrated approach combining multiphase, turbulence, cavitation, and broadband noise models to characterize the distributions of velocity, pressure, phase, turbulent kinetic energy, and noise power. The results reveal that noise intensity scales positively with pressure drop across the valve, and regions of elevated noise coincide with areas of high turbulent kinetic energy. Under liquid-phase inflow, cavitation occurring downstream of the throttling orifice generates pronounced noise predominantly on the right side of the valve needle. In contrast, when two-phase flow enters the valve, the high-velocity gas jet accelerates through the orifice, producing strong noise on both sides of the needle. Two distinct noise generation mechanisms are identified based on upstream flow conditions. The first is cavitation-induced noise, localized near the needle tip, where rapid phase change creates intense unsteadiness that decays quickly as cavitation subsides. The second is backflow-induced noise, originating at the valve bottom where the impinging jet generates large-scale recirculation and momentum exchange with the mainstream, producing sustained noise over an extended region that gradually dissipates downstream. The overall variation trend of noise through flowing direction firstly decreases, then increases and finally decreases. The maximum average noise power in selected planes reaches 112 dB with annular flow appearing before EEV.

Helical coil once-through steam generators, owing to their advantages of compact structure and high thermal efficiency, are applied in fourth-generation nuclear reactors. During the process where the subcooled water on the secondary side of the OTSG is heated into superheated steam, density wave oscillation is prone to occur. An experimental study was conducted on full-scale double-parallel helical tubes. The influence law of inlet sub-cooling on the DWO boundary was obtained, which is nonlinear and non-monotonic. As the inlet subcooling increases, the critical heat flux first increases, then decreases, and increases again, with two inflection points. It generally presents an "S-shaped" law in the dimensionless boundary map. Increases in the inlet throttling coefficient, system pressure, and inlet flow rate enhance system stability and do not affect the occurrence of the "Sshaped" law. The "S-shaped" stability boundary is affected by the heat load applied to the gas-liquid two-phase section. The oscillation period variation law and pressure drop distribution were described. At relatively low inlet quality (less than-50 %), the ratio of oscillation period to mixed transport time (Omega/tau) is less than 0.5; as the inlet quality increases, Omega/tau gradually increases; when the inlet quality is-3.61 %, the ratio of fluctuation period to mixed transport time is greater than 2. The ratio of the pressure drop in the gas-liquid two-phase section to that in the subcooled fluid section exhibits a fixed relationship similar to an inverse proportion. This study provides an important scientific basis for the safe operation of new-type nuclear energy systems.

In lead-bismuth fast reactor, Lead-Bismuth Eutectic (LBE) is used as a coolant to transfer heat from the primary loop to the secondary loop through the helical-coil once-through steam generator (HC-OTSG). Due to the complexity of the HC-OTSG, there is no thoroughly validated model available for liquid-metal cross-flow and heat transfer over helical coils. An experimental system for coupled flow and heat transfer between LBE and hightemperature high-pressure water was established. The experimentally and numerically investigates the coupled heat transfer characteristics between LBE and high-temperature high-pressure water in HC-OTSG. A heat transfer model for liquid LBE flowing over helical coils on the primary side of the HC-OTSG was established. This model has been validated using the experimental data from this study and published literature, with the maximum error not exceeding 4%. The study analyzes how different thermal parameters affect the coupled heat transfer between LBE and water. Results show that heat flux distribution between primary and secondary sides is highly nonuniform. The maximum heat flux can be over 190 times the minimum heat flux. Primary side pressure drop and heat transfer coefficient are sensitive to primary side flow rate changes. Secondary side pressure drop, heat transfer zone lengths, and heat transfer coefficients are mainly affected by secondary side flow rate. Inlet temperatures of primary and secondary sides have minimal impact on overall heat transfer coefficient and pressure drop of HC-OTSG. This research provides important scientific basis for the design and operation of Lead-bismuth fast reactor helical coil steam generators.

During deep peak shaving process, the flow instability may occur within the water-cooled-wall of supercritical boiler, posing a serious challenge to the thermal system's security. In this study, a general model based on the time-domain method with customized heat transfer and multi-tube parallel model is developed to analyze the flow instability in water-cooled-wall system. The model was verified by a comparison between the computational results and experimental data. Building on this model, the flow instability characteristics of the water-cooledwalls in a 600 MW supercritical once-through boiler were analyzed under Boiler Maximum Continuous Rating (BMCR), 75 % Turbine Heat Acceptance (THA), and 30 % THA. The results indicate that during deep peak shaving, the stability is relatively poor at low-load conditions. As the load decreases, the duration of oscillations increases from 81 s to 115 s (increased by 41.98 %). For multi-tube parallel under low-load, the influence of various thermal parameters on flow instability was also investigated. When the number of parallel tubes increases to 20 and 40, the critical heat load shows an increase to 0.51 % and 1.02 %, reaching 39.5 kW m-2 and 39.7 kW m-2, respectively. Furthermore, it increases almost linearly with inlet pressure, significantly with inlet mass flow rate, and decreases with increasing inlet temperature. The inlet mass flow rate and temperature significantly influence the threshold heat flux.

T In fourth-generation advanced reactors, flow instability and oscillations within heat exchange tubes of steam generators can arise due to uneven flow distribution and other complex factors, posing risks to safe operation. Such instabilities may lead to fluid mixing, oscillations, and significant fluctuations, thereby increasing system complexity and unpredictability. Installing a throttling element at the inlet of the steam generator’s heat exchange tubes can effectively enhance the inlet resistance coefficient, mitigate the occur-rence of flow instabilities. Due to the complexity of throttling structures, re-search on their design for steam generators is limited. Traditional empirical methods for calculating resistance coefficients often yield considerable inac-curacies. This study presents a novel T-shaped orifice throttling element de-signed for steam generators in fourth-generation advanced nuclear energy systems. Through a combination of numerical simulations and experimental validation, various structural parameters of the T -shaped orifice throttling el-ement were developed and manufactured, allowing for the assessment of the resistance characteristics across a wide range of flow conditions. The results reveal that the resistance coefficient of the innovative $\mathbf{T}$-shaped throttling device can fit for different operational requirements in steam generators for fourthgeneration advanced nuclear energy systems. The resistance coeffi-cient shows significant sensitivity to both the aperture size of the $\mathbf{T}$-shaped orifice and the structural characteristics of the baffle. Furthermore, the re-sistance coefficients of throttling devices with varying structural parameters maintain relative stability across a range of Reynolds numbers. A mathemat-ical relationship was established to correlate multiple structural parameters and the resistance coefficient. This study establishes a foundation for the further investigation and development of practical designs and optimizations of throttling elements for fourth-generation advanced nuclear energy sys-tems.

T-junction is an essential component in piping system of various thermal systems. When hot and cold fluid mixing in the T-junction, several compound mechanisms (like turbulent mixing, turbulent penetration, fluid stratification) make the mixing characteristics more complex. To clearly reveal such mixing mechanism with non-isothermal fluids, an experimental study was conducted with Ultrasound Doppler Velocimetry (UDV) and fast-response thermocouples bundle. The results show that the local velocity uncertainty of the UDV is within 10%, the uncertainty of the thermocouple bundle is 0.5°C, and the response time is 66.7 ms. After verification, the mixing characteristics between the main and branch pipe under different momentum ratios and temperature differences were discussed. It is shown that as the momentum ratio decreases, the location of the most intense radial temperature fluctuations and velocity fluctuations shifts towards the lower wall. At the same time, the peak flow rate in the cross-section increases by 35.7% and the main branch fluid mixing is more homogeneous. As the temperature difference increases, the thermal stratification is more pronounced and the velocity fluctuation peak moves towards the upper wall of the pipe.

The supercritical CO2 2 (sCO2) 2 ) Brayton cycle for the lead-cooled fast reactor (LFR) is an ideal power generation system for the distributed energy supply in remote islands. To figure out the optimal operating modes of the MW- scale sCO2 2 LFR unit in different load demands, this work performs a dynamic simulation based on the developed control modules. A parametric analysis is conducted about the effects of rotational speed, split ratio, and main gas temperature on the dynamic characteristics. Control strategies are further studied based on the thermodynamic performance and safety under four variable temperature load regulation modes and three fixed temperature rapid load regulation modes. Results show that the tracking alpha optmode opt mode has the highest average net efficiency (eta netav ) of 19.13 %. The tracking alpha safe mode allows compressors to operate in the safest range by sacrificing a little eta netav . Excellent load change rates are revealed by using the main circuit regulating valve control mode and the turbine bypass control mode, with-12.48 %Pe/min & 11.92 %Pe/min, and-8.25 %Pe/ min & 9.70 %Pe/min, respectively. Though the load change rate of the RS control mode is-3.96 %Pe/min & 3.47 %Pe/min, its eta netav is higher. Our work guides the efficient, flexible, and safe operation of the sCO2 2 LFR unit.

Abstract In the combined system of lead cooled fast reactor (LFR) and supercritical carbon dioxide (S-CO2) Brayton cycle, the intermediate heat exchanger plays a key role in the whole power system. However, the existing heat exchanger can not meet the trend of miniaturization of lead cooled fast reactor. Considering the thermo-physical properties and heat transfer behaviors in both S-CO2 and liquid lead bismuth eutectic (LBE) are significantly different, an asymmetric compact coupled heat exchanger learning from Honeycomb structure is proposed. Through numerical simulation, it is found that the thermal resistance mainly exists in the cold side. In order to enhance the heat transfer at the S-CO2 side, the fin tube is adopted at the cold side. The results show that the heat transfer performance and friction factor of the heat exchanger increase with the increase of fin height, width and number of fins due to the increase of heat transfer area. When the fin height is increased, PEC gradually increases at low inlet velocity, and then decreases at high inlet velocity; When the fin width is increased, PEC increases first and then decreases at low inlet velocity, and decreases gradually at high inlet velocity; With the increase of the number of fins, PEC showed an increasing trend at different inlet velocities.

To study the corrosive behavior of metal materials in the pseudocritical region of supercritical fluid and explain the abnormal mechanism in corrosive within the pseudocritical region, a corrosive experimental platform for supercritical fluids was built. Three different candidate materials for Supercritical Water Reactor (i.e. Q235 low carbon steel, 316 L austenite stainless steel and 3Cr13 martensitic steel) were selected and reacted for 200 h in the pseudocritical region (375.6 & DEG;C, 22.5 MPa) and gas-like region (405.6 & DEG;C, 22.5 MPa) respectively. The results show that 316 L exhibits abnormal corrosive exacerbation in the pseudocritical region with a corrosive rate 1.67 times that of the gas-like region. Considering the special variation of physical properties in pseudocritical region, the enhanced kinetic effect is further analyzed. It is found that the migration of corrosive media such as oxygen to the material matrix is accelerated, which aggravates the corrosive products shedding and freeing. The present study can provide a basis for improving the anti-corrosive performance of materials under supercritical fluid environments and providing a safe operation of the Supercritical Water Reactor.

超临界二氧化碳布雷顿循环与铅冷快堆的结合被认为是最为理想的动力循环之一,系统通过中间换热器传递热量,其性能影响着整个发电系统的高效与安全运行.由于超临界二氧化碳和液态铅铋合金(LBE)物理性质和热输运性质差异显著,对称式结构无法匹配两侧工质的换热要求,构建了1种非对称式紧凑式耦合换热器,采用数值模拟方法研究了超临界二氧化碳与液态铅铋合金耦合换热特性.结果表明:提升冷侧流体入口速度会显著增强换热;增加热侧LBE入口速度时,总换热系数先降低后增加;提升换热器冷热流体入口温度,换热器的换热系数先减小后增大,存在最优值;在拟临界区内,强浮力作用会大幅提升冷侧换热,而加速效应则抑制换热.

液态金属快堆/太阳能光热系统与超临界二氧化碳(S-CO2)布雷顿循环发电系统深度融合,必将引领能源动力领域革命性发展.由于液态金属与S-CO2的特殊物理性质,液态金属普朗特数远低于常规流体,S-CO2 的物理性质奇异性变化,其流动换热特性与常规流体存在显著差别,其流动与传热机理比较复杂,耦合传热机理尚不明朗.本文归纳总结了国内外关于S-CO2、液态金属、耦合换热与耦合换热器在实验、数值模拟、传热预测模型的主要研究成果,指出液态金属与S-CO2流动换热及其耦合传热研究中存在的问题,为先进动力循环系统以及多工质耦合动力系统的设计和安全运行提供参考依据.

In the combined system of lead-cooled fast reactor and supercritical carbon dioxide (S-CO2) Brayton cycle, the intermediate heat exchanger plays a key role in the whole power system. However, the existing heat exchanger cannot meet the trend of miniaturization of lead-cooled fast reactors. Considering the thermo-physical properties and heat transfer behaviors in both S-CO2 and liquid lead bismuth eutectic are significantly different, an asymmetric compact coupled heat exchanger learning from the Honeycomb structure is proposed. Then the effect of the Reynolds number on the coupling heat transfer is discussed. When the Reynolds number of the cold side was changed from 57600 to 145000, the heat transfer coefficient of the heat exchanger increases by 79%, but when the Reynolds number on the hot side is changed from 29600 to 118000, the heat transfer coefficient only increases by 4.6%. To enhance the heat transfer and reduced thermal resistance on the S-CO2 side, a wavy channel was used. The results showed that the wavy channels could significantly improve the field-synergy angle. In the smooth pipe, the averaged field-synergy angle is 88.7°, while in the wavy channel, the averaged field-synergy angle becomes 84.1° at α = 1.5. With the increase of wavy amplitude in S-CO2 channel, the heat transfer coefficient and the friction factor increased, but the comprehensive heat transfer coefficient is in non-monotonic variation. The overall heat transfer coefficient of the wavy channel is 1.56-1.81 times than that of the straight channel in the range of ReSCO2 = 86700 ~ 145000.

The static and dynamic corrosion experimental platforms of supercritical fluid reactor were used for the static and dynamic corrosion test of Q235, 304, 316L, P91, N80 and 3Cr13 in the supercritical water pseudo-critical region (22. 5 MPa, 375. 6 degree celsius) and gas-like region (22. 5 MPa, 407. 6 degree celsius) for 72 h. The results show that the dynamic corrosion rate of materials in supercritical water environment is significantly higher than the static corrosion rate, and the flow accelerates the corrosion process, in which 304 is increased by more than 4 times; the strengthening effect of dynamic conditions on corrosion mass gain is weakened with the decrease of corrosion resistance. The factors that exacerbate corrosion under dynamic conditions are: flow shear force accelerates the movement of the corrosive medium in the supercritical fluid to the substrate surface, promoting the corrosion chemical reaction; the flow shear force scours the material surface, promotes the dissolution of Fe on the material surface, and accelerates the corrosion chemical reaction; the erosion effect of shear force promotes the detachment of corrosion product crystals during the formation process of the wall, accelerating the corrosion process.