Addressing the issues of poor thermal conductivity in traditional Kelvin structure-based heat sinks and the suppression of natural convection in the TPMS structure-based heat sinks. The Half Primitive structure proposed in this study is designed to investigate and validate the effects of enhancing thermal conduction across thermally contacting interfaces and promoting heat transfer induced by internal natural convection. Numerical simulations based on the sensible heat capacity method are conducted to analyze the thermal behavior. The numerical model has been validated, and the simulation results are in good agreement with the test results. The effects of heat transfer properties, including temperature, average heat transfer coefficient (havg), and Grashof number are discussed. The analysis results indicate that the enhancement of thermal conduction across thermally contacting interfaces and the promotion of internal natural convection significantly improve the thermal performance of the PCM-based heat sink. After enhancing the thermal conduction at the bottom, the Half Primitive structure reduced the base temperature difference between the Kelvin structure and the primitive structure by 73 % at 650 s. Following the enhancement of internal natural convection, taking the average base temperature difference between pure conduction and convection heat transfer scenarios as an example, the average temperature difference of the Half Primitive structure is 8.64 % higher than that of the Primitive structure. Moreover, the havg of the Half Primitive structure is 36.3 % higher than that of the Kelvin structure, and the difference in havg between the Half Primitive and Primitive structures narrows to approximately 4.8 %.

During the operational process of electronic components, excessive heat generation results in significant temperature elevation. This elevated temperature poses a significant risk to their service life. Regarding the issue of efficient thermal management of electronic devices in enclosed spaces experiencing high heat flow, a thermal management scheme for electronic equipment using TPMS and a PCM-based heat sink is proposed. The apparent heat capacity method is employed to simulate the melting process of the PCM-based heat sink. The effects of structural parameters w1, w3, and C of TPMS structures on the heat transfer characteristics (including base temperature, liquid fraction, average cell temperature, and average heat transfer coefficient) of the PCM-based heat sink during the melting process are discussed. A temperature testing platform is established. Experimental research is performed to investigate the effect of TPMS structures with two different printing prototypes (Sample 1, and Sample 2) on the heat sink during the intermittent cycle. The results indicate that increasing the parameters C and w1 significantly improves the average heat transfer coefficient (HTC) of the heat sink. When C increases from 0.3 to 0.7, the average HTC increases from 307 W/(m2 & sdot;K) to 358 W/(m2 & sdot;K). When w1 increases from 1 to 3, the average HTC increases from 284.5 W/(m2 & sdot;K) to 321.3 W/(m2 & sdot;K). Sample 1, possessing superior thermal conductivity, exhibits better heat transfer performance. When the temperature achieves a stable periodic variation, the base temperature of Sample 1 stabilizes within the range of 310 K-340 K. And Sample 2 stabilizes within the range of 315 K-350 K.

In the later stage of cycle steam stimulation(CSS), the production capacity decreases and the water cut increases.As an alternative development method to cycle steam stimulation, the flue gas-assisted cycle steam stimulation(FGACSS) has been widely applied in heavy oil development.However, existing research has not been able to reveal the mechanisms of different components in different zones, making it difficult to provide effective guidance.In this paper, based on the analysis of production dynamics from typical wells in the Moltuk field, a mechanistic model of FGACSS is constructed.The different zones of action for different components are delineated, and microscopic displacement experiments are conducted to study the flow states of oil, gas, and water in different zones at the microscopic level.The research results show that, based on the distribution of different components and reservoir parameters, the wellbore to far-well region can be divided into three zones: the high-temperature zone (0-25m), recombination zone (25-100m), and increased pressure zone (100-200m).In the high-temperature zone, the main mechanism is the viscosity reduction through condensation of steam.The flow state is wateroil, with different flow characteristics in large and small pores.In the recombination zone, viscosity reduction is achieved through heat conduction and CO2 dissolution.The presence of CO2 and N2 in the gas phase increases the pressure, and the flow state at the microscopic level is water-oil-gas-oil.The hot water and non-condensable gas displace different types of residual oil.In the increased pressure zone, only N2 is present, and the pressure continuously decreases.The flow state is gasoil.Based on the dynamic analysis of typical wells, this paper proposes a multi-composition zoning coupling mechanism, providing reference for further research on FGACSS mechanisms and adjustments to production measures.

Steam-assisted gravity drainage (SAGD) is one effective and well-established technology for recovering heavy oil and bitumen resources.Extensive research has been conducted on data-driven models to evaluate the production performance of the SAGD process.The artificial neural network (ANN) is a commonly used machine learning method.However, it is crucial to explore other machine learning methods such as Symbolic Regression (SR), Extreme Gradient Boosting (XGBoost) and Random Forest (RF) using field data.In this study, firstly, a data set consisting of thirteen input/output attributes describing production-related properties and production characteristics was extracted from Long Lake field data.Secondly, three different machine learning methods, including Neural Networks (ANN), Random Forest (RF), Extreme Gradient Boosting (XGBoost) and Symbolic Regression (SR), were employed to establish a relationship between the input and output parameters in the different data sets.Subsequently, a range of models were created, evaluated, and compared.Furthermore, the impact of two feature scaling methods, namely standardization and normalization, on the accuracy of a series of prediction models was explored.Lastly, the sensitivity of the input parameters was analyzed.Analysis of the forecasting results obtained from different models leads to the following conclusions.The study found that standardization and normalization significantly enhance the performance of the artificial neural network model, with standardization being more effective.However, the impact of data scaling on integrated learning models (random forest and extreme gradient boosting tree) is minimal.Interestingly, for models based on symbolic regression algorithms, not using data scaling yields the best results.Both artificial neural network and symbolic regression algorithms demonstrate significant advantages and are suitable for

The built-in air-conditioning and ventilation system of modern conventional submarines still adopts duct ventilation, which has high working noise, high energy consumption, poor dehumidification effect, and is mainly inter-cooled. For the air quality, hot and humid environment and comfort requirements in the submarine cabin. This project proposes an energy-saving cold storage air-conditioning system suitable for submarines. It adopts the air control method of temperature and humidity independent processing, and combines solution dehumidification and cold storage technology to independently control the temperature and humidity of the cabin, so as to achieve the purpose of efficient dehumidification and energy saving. The system makes full use of the limited space inside the submarine, reduces the energy consumption of refrigeration, improves the underwater endurance and concealment, and provides a healthy and comfortable air environment for the crew of the submarine, which has important strategic value.

Interfacial solar steam generation, with high energy efficiency, promotes the solar desalination technology to a new era. However, the problem of low freshwater yield in enclosed distillation system owing to optical loss and insufficient condensation capability remains a challenge. In this work, a reversed interfacial solar distillation system is proposed by combining Janus fabric with comprehensive thermal management to significantly enhance the freshwater yield. Recycled cotton fabric is used to fabricate the low-cost Janus fabric with carbon black@ -silicone on the top side via a simple and scalable pre-wet coating method. The Janus fabric with high sunlight absorbance (98.0 %) and good sealing properties remarkably guarantees the downward vapor generation to eliminate the optical loss, resulting in the improved freshwater collection of the distiller. Comprehensive thermal management is designed for the distillation system to reduce the heat loss of the evaporator and enhance the condensation effect of the condenser. The optimal Janus fabric-based interfacial solar distiller achieves an outstanding water yield of 1.17 kg m- 2h-1 and an efficiency of 78 % under one sun (1 kW m-2) illumination. This work presents a novel design of a high-performance interfacial solar distillation system, offering the po-tential for large-scale and low-cost industrial production.

In order to improve the performance of pilot flame propagation to the core flow, a novel strut design was proposed for the trapped vortex cavity flameholder. Experiments were conducted under high subsonic flow conditions to investigate the influences of strut on the ignition performance and flame propagation performance of trapped vortex cavity combustor. Furthermore, the flame development was acquired using a high-speed camera and the flame information and the flow field were combined to explicate the flame stabilization mechanisms of two flameholder layouts. The results showed that, both flameholder layouts achieved reliable ignition and flame stability under inlet flow velocity lower than Ma = 0.42. Cavity combined with strut weakened the ignition performance of the trapped vortex cavity-only flameholder based combustor, but improved the blowout performance and enhanced the flame stability. Compared with the cavity-only flameholder layout, the lean ignition equivalence ratio of the cavity-strut flameholder layout was increased of 14.6%, and the lean blowout equivalence ratio was decreased by 56.2%, under the inlet flow at 600 K. Strut changed the original flame propagation path of the cavity-only layout, and caused the flame stabilization mechanism change from cavity flame stabilization to strut flame stabilization. Although the change of flame stabilization mechanism prolongs the ignition delay time, it enhances the flame stability of the combustor. Moreover, the flame propagation ability to the radial direction behind the cavity combined with strut is enhanced, which is more suitable to the engineering combustor with higher requirements on circumferential flame propagation.

为有效改善蒸馏膜(MD)的高能耗问题,提出一种低能耗的太阳纳米光子蒸馏膜(NESMD)组件,对其热力学性能开展研究,并分析关键操作参数对其热力学特性的影响规律.研究结果表明,温度极化是导致MD技术高能耗的主要内因,NESMD组件采用面加热方式进行料液加热,不存在温度极化现象,因此具有显著的节能优势.在相同进料温度和进料速度下,NESMD组件相较于MD组件,温度极化系数和热效率均有显著提升,NESMD组件热效率受潜热影响最大,可采取低进料速度和高进料温度来提高热效率;当将聚乙烯醇(PVA)涂层作为功率输入段时,NESMD和MD组件均存在最佳输入段长度使得热效率最大;NESMD组件相较于MD组件具有更好的拓展性和更长的活性长度.上述性能规律为进一步优化结构提供了科学依据.

为了探究采用射流预冷技术之后加力燃烧室性能,开展了不同喷嘴布置方案、喷水量和来流温度对预冷效果的影响研究.对射流预冷发动机工作过程进行了简化,建立了加力燃烧室进口前段射流预冷喷水特性计算的数学模型.同时搭建了小型试验台,通过与试验结果的比对验证了该模型的准确性,并利用该模型对射流预冷效果进行了仿真预测.结果表明:提高喷嘴数量与布置均匀性能够小幅度改善预冷效果;当来流温度不变时,射流预冷喷射腔室出口处的液态水蒸发量随着喷水量的增加而提高,但蒸发率却处于下降的趋势;当喷水量达到2%时,加力燃烧室燃烧效率对比不喷水工况会有一定的提升;喷水量达到4%以后,加力燃烧室出口温度及燃烧效率随着喷水量的提高而降低;喷水量大于8%以后,恶化了加力燃烧室(V型火焰稳定器)贫油熄火极限与燃烧效率;喷水量达到最大10%时,油气比需从原来设计工况的0.052上升到0.064才能保持稳定点火且对比不喷水时工况,加力燃烧室出口温度由1860K下降到1373K,燃烧效率由80.2%下降到69.2%.

The objective of the present work is to research the dynamic thermal performance of the solar power plant during the phase change material (PCM) capsule heat storage tank discharging process. Therefore, a transient, one-dimensional two-phase model for a packed bed latent heat storage unit and a comprehensive concentrating solar power generation system that combines a CO2 Brayton cycle and organic Rankine cycle were integrated. The influences of the key parameters of the packed bed PCM capsule heat storage tank on the overall power output and thermal efficiency of the system during discharge have been investigated, including the heat transfer fluid (HTF) velocity, the diameter of the PCM capsule, and the height of heat storage tank. The orthogonal analysis method is selected in this article, and the results showed that the maximal transient power output and overall power output of the actual combined cycle mode are decreased about 22% and 25%, respectively, in this research, compared with the idea Carnot cycle mode. That the HTF velocity in the thermal energy storage tank can be used to control the transient power output of the solar thermal power system. Using the small-sized filler capsule is an effective method to increase the thermal performance of the concentrated solar power (CSP) combined cycle system. Moreover, the corresponding discharging time is increased obviously, and the CSP with a high packed bed height can generate a more stable power output value during thermal energy discharging.

针对给定太阳日辐射曲线,研究集成蓄热单元的太阳光热系统的整体能量的动态转化特性及关键参数影响规律.结果表明:填料床总储热量与传热流体进口流速呈非线性变化,当传热流体进口流速uf=0.006 m/s时,填料床总储热量最大;在给定填料总容量和uf=0.006 m/s的条件下,填料床高径比为5的填料床具有更高的储热能力;在该计算条件下,uf=0.006 m/s、填料床高径比为5及填料量相对值为1时,太阳光热能实现最大程度上的转化和储存.

Installing the air curtain for painting drying workshop is an effective method for continuous vehicle in and out. A top injection air curtain is designed for the high temperature vehicle painting drying workshop in this research. Based on the numerical simulation method, the effect of key operating parameters and working state of the air curtain on the stability and thermal dissipation performance of air curtain have been investigated. The results showed that increasing both the air curtain injection velocity and injection angle improved the stability of the top injection air curtain. Both the optimized air curtain injection velocity and the air curtain injection angle are obtained to achieve the lowest thermal dissipation effect at the fixed workshop height. The stability of the air curtain declines sharply and the thermal energy dissipation of the workshop increased obviously at high workshop height. With the vehicle skeleton passes through the air curtain, the stable gas barrier is destroyed, and the thermal dissipation is increased compared without vehicle passing. The low air curtain jet velocity is recommended with vehicle through the air curtain. Moreover, the small distance between the car bottom to the ground, and the quickly vehicles passing air curtain are suggested in actual operation.

This paper presents a new type of circulation system combining heat pump and liquid gap membrane distillation (LGMD) for the concentration of sulfuric acid solution. The proposed hybrid system not only has a simpler flow configuration, but it also demonstrates significant thermal performance advantages. Based on the principle of conservation of mass and energy, a mathematical model is established in Aspen Plus to simulate working conditions. Through varying the relevant parameters, the solution with low boiling point elevation to achieve the maximum water production gain to output ratio (GOR) value was obtained, which is approximately 33 times that of the conventional system under the given condition in this research. Given the temperature difference between the condenser and the evaporator in the heat pump cycle, the higher membrane flux and the maximal value of GOR are obtained at the high feed temperature. However, increasing the molar fraction of the feed solution sharply decreases both the membrane flux and GOR, especially at high feed solution temperatures. Additionally, it was found that the high GOR are obtained when selecting the high boiling point working fluids. Therefore, these results can provide significant references for the further implementation and optimization of the proposed system.

对烘干室气幕密封特性进行数值模拟研究,讨论送风速度和角度对气幕密封性能的影响.结果表明,相比上送风式气幕,改进型气幕密封性能较优,其上部喷口送风角度取35°～40°,速度取9 m/s,侧部喷口送风速度取3 m/s,角度取30°～35°时气幕密封性能最佳,密封效率为77.8％.若送风速度过小,无法形成完整气幕,而送风速度过大则存在射流高温气体冲击烘干室底部现象;烘干工件处于气幕喷口时影响气幕墙的形成,进口延长段温度升高36℃,故烘干作业时待烘干工件应置于进口延长段前段.

Removing moisture in the wet farm products through the open air ventilation is a traditional postharvest treatment method. However, its overall energy consumption is high and the drying time is long. Here, a combined system is proposed through integrating a bottom organic Rankine cycle (ORC) to a top closed farm products air drying cycle to save energy and decreasing the drying time. Based on a steady state thermodynamic model without any losses, a theoretical work on thermal performance the proposed system has been conducted. The key operation parameters and suitable operation conditions for both the prominent energy saving ratio and high moisture extraction characteristics have been analyzed. The calculation results showed both the prominent energy saving and high moisture extraction performances can be achieved at the low ORC evaporating pressure condition, but the optimal energy saving performance and the moisture extraction performance could not be achieved simultaneously. Increasing dew point temperature of the humid air leaving the drying chamber improves both the energy saving and moisture extraction performances of the drying system significantly. Under the working conditions in this research, with the dew point temperature value of the humid air leaving the drying chamber over 323 K, the optimal energy saving performance is achieved at a fixed low ORC evaporation pressure. But, the prominent energy saving and high moisture extraction performances could not be accomplished simultaneously, with the dew point temperature value of the humid air leaving the drying chamber lower than 323 K.

热泵膜蒸馏是一种新型的膜分离技术,在处理高浓度盐水方面具有很大的优势,而目前的热泵膜蒸馏系统存在渗透量较低、冷却水消耗量大等问题.为提高渗透量、减少冷却水的消耗,设计了一种新型液隙式热泵膜蒸馏的海水淡化系统,通过在Aspen Plus中自定义膜模块建立经过实验验证的系统仿真模型,研究了进料液温度、渗透侧温度及进料流量对系统膜通量及能效比等热力参数的影响.结果 表明,渗透侧温度降低可引起渗透量增加和能效比减小,且在低渗透侧温度情况下渗透侧温度的改变对能效比影响更大.随着渗透侧温度变化,存在一个渗透侧温度使造水比最大且吨水能耗最小,研究工况下最大造水比可达3.42,最小吨水能耗为463 MJ/t,且该最佳渗透侧温度随进料液温度增加而增加.进料液流量增加可引起渗透量和能效比增加,引起吨水能耗升高和造水比降低,当进料液流量小于3 L/min时,进料液流量增加对吨水能耗和造水比的负面影响较显著,进料液温度为50℃时,料液流量从1.5 L/min增至3 L/rin,造水比的降低幅度可达33.5％;料液流量从4.5 L/min增至6L/min时,造水比的降低幅度降至10.6％.

真空保温技术广泛应用于LNG的储藏和运输领域,利用真空层进行隔热是一种有效的保温手段.模拟研究了带有聚四氟乙烯支撑环的三维输送管道的散热过程,讨论了真空层压力、环境温度、对流换热系数对散热性能的影响规律,并与热阻分析结果进行了对比验证.结果表明:随着真空层压力从0.001 kPa升至5.33 kPa,换热量从83.82 W升至124.72 W,0.001 kPa到2 kPa段的换热量升高的最快.随着外界温度从268.15 K升至298.15 K,换热量从97.54 W升至120.56 W,并且呈线性增长趋势.随着外界对流换热系数从5 W/(m2·K)增至25 W/(m2·K),换热量从112.1 W增至127.8 W.管间区域的空气在上方形成一个温度为290 K左右的高温区,下方形成一个温度为80 K左右的低温区,两区域之间形成环流,环流中部的空气流动速率最快为0.26 m/s.

基于欧拉方法,考虑温度对热物性的影响,耦合相间换热和界面浓度模型,模拟鼓泡塔内气体和熔融盐的换热行为.模拟分析熔融盐温升速率、体积换热系数和塔内熔融盐温度分布的规律,结果表明熔融盐温升速率和体积换热系数随表观气速的增加而增加,随初始液面高度的增加而减小,中心处熔融盐温度沿轴向高度增加逐渐减小,熔融盐温度径向分布随液位高度的增加逐渐趋于均匀.

基于能量梯级利用热力系统耦合理论,集成了一种适合热敏性农副产品烘干的新型空气干燥循环系统,系统可得到热敏性干燥产品,同时回收湿空气冷凝废热用于有机朗肯循环(ORC)系统对外做功.对关键部件湿空气冷凝器建立传热传质数学模型并经实验验证,考察了关键操作参数对系统脱水速率及节能效果的影响.结果 表明,湿空气湿度是影响该系统凝水和节能的最关键参数,该系统凝水及节能特性均随湿空气湿度提高而改善;当干燥箱出口湿空气含湿量温度一定时,新型空气干燥循环凝水量主要受到干燥箱出口空气流量的影响,系统的凝水量和换热量均随湿空气质量流量增加先增加后降低,在0.10～0.15kg/s出现极大值;系统净输出功随ORC底循环蒸发温度提高显著增加.本系统下的热敏性农副产品烘干建议选择低空气流速、低烘干温度,推荐的ORC底循环蒸发温度为313～323 K.