一种可用于压力容器水压试验的蒸汽腔密封装置

根据压力容器水压试验过程中蒸汽腔模拟件的密封要求,设计一种可用于蒸汽腔模拟件的密封装置。介绍密封装置主要组件如蒸汽腔模拟件、径向密封装置的设计和结构,以及蒸汽腔模拟件密封装置的装配,并通过试验验证该密封装置的可靠性。

直井-水平井组合SAGD物理模拟研究

蒸汽辅助重力泄油（SAGD）技术是一种开发超稠油的经济有效方式，国内油藏在直井吞吐后普遍采用直井一水平井组合SAGD开发。以曙一区杜84块兴VI组油层油藏地质参数、流体性质为基础，采用高温、高压三维比例物理模拟系统模型来描述超稠油油藏蒸汽吞吐后转蒸汽辅助重力泄油的开发过程，并对实验过程中蒸汽腔变化进行监测分析，根据蒸汽腔发育特征将蒸汽腔的形成和发育过程分为汽腔形成、汽腔扩展和汽腔下降等3个阶段，同时结合温场发育状况及产油量、含水率等实验数据，可以将直井一水平井组合SAGD生产阶段划分为吞吐预热阶段、汽腔形成（SAGD驱替阶段）阶段、汽腔扩展阶段和汽腔下降阶段。物理模拟直井一水平井平组合SAGD实验表明，最终注入倍数为2．8时．阶段采出程度可以达到58．5％，物理模型平均剩余油饱和度为19．40％。

加热器产品工作过程模拟演示

针对某些工业产品其工作原理较为复杂,如加热器的工作原理涉及水、蒸汽的状态变化。通过计算机三维建模工具建立产品的三维实体模型,并根据工作情况模拟水、蒸汽的状态变化,实现整个过程的可视化,有助于产品的设计和改进。

基于VisPy的油藏蒸汽腔形态变化三维动画控制

作为国外一种成熟高效的稠油开发技术,蒸汽辅助重力泄油(SAGD)在国内的应用也日渐成熟。因此,开发SAGD软件以辅助实际开发有着重要的现实经济价值。而在设计与实现该软件的过程中,需要利用三维可视化技术来准确反映油藏蒸汽腔的形态变化。结合实际SAGD开发软件需求,以PyQT5为GUI开发工具,基于当前较为新颖的高性能三维动画库VisPy,讨论了蒸汽腔三维展示部分中动画控制功能模块的功能需求、技术选型、详细功能设计和实现过程,给出了测试实例和结果。该工作对其他类似系统中设计与实现三维动画控制方案有着较强的实际指导意义,同时对新兴起的Python 3D可视化库VisPy的使用有一定的借鉴作用。

大连星海国际展览中心空调系统设计

针对位于寒冷地区的该超高层建筑，阐述并分析了其空调系统的具体设计方案。热源系统采用市政海水源热泵和市政蒸汽；空调水系统根据设备及管道的承压、建筑功能和业主的要求竖向分为2～3个压力分区；洗衣房工艺及空调加湿用蒸汽由市政蒸汽和蒸汽锅炉联合提供；租户办公区的数据机房采用冷却塔供冷。利用CFD数值模拟软件，分析规划了该建筑区的室内、外微气候状况，为合理的规划设计提供科学的理论依据。

Numerical Study on Flow-induced Noise for a Steam Stop-valve Using Large Eddy Simulation

The noise induced by the fluctuant saturated steam flow under 250 °C in a stop-valve was numerically studied.The simulation was carried out using computational fluid dynamics（CFD） and ACTRAN.The acoustic field was investigated with Lighthill＇s acoustic analogy based on the properties of the flow field obtained using a large-eddy simulation that employs the LES-WALE dynamic model as the sub-grid-scale model.Firstly,the validation of mesh was well conducted,illustrating that two million elements were sufficient in this situation.Secondly,the treatment of the steam was deliberated,and conclusions indicate that when predicting the flow-induced noise of the stop-valve,the steam can be treated as incompressible gas at a low inlet velocity.Thirdly,the flow-induced noises under different inlet velocities were compared.The findings reveal it has remarkable influence on the flow-induced noises.Lastly,whether or not the heat preservation of the wall has influence on the noise was taken into account.The results show that heat preservation of the wall had little influence.

Numerical Simulation of Direct-contact Condensation from a Supersonic Steam Jet in Subcooled Water

The phenomenon of direct-contact condensation,used in steam driven jet injectors,nuclear reactor emergency core cooling systems and direct-contact heat exchangers,was investigated computationally by introducing a thermal equilibrium model for direct-contact condensation of steam in subcooled water.The condensation model presented was a two resistance model which takes care of the heat transfer process on both sides of the interface and uses a variable steam bubble diameter.The injection of supersonic steam jet in subcooled water tank was simulated using the Euler-Euler multiphase flow model of Fluent 6.3 code with the condensation model incorporated. The findings of the computational fluid dynamics（CFD） simulations were compared with the published experimental data and fairly good agreement was observed between the two,thus validating the condensation model.The results of CFD simulations for dimensionless penetration length of steam plume varies from 2.73-7.33,while the condensation heat transfer coefficient varies from 0.75-0.917 MW·（m ^2 ·K）^ -1 for water temperature in the range of 293-343 K.

蒸汽驱模拟新发展

加密网格模型能够描述近井垂直蒸汽超覆,稠油蒸汽驱是重力泄油过程而不是驱替过程得到证实,而且模型的非封闭性边界导致蒸汽带压力与现场实际压力相似。初期生产井蒸汽吞吐的常用作业方法降低了压力,加速了蒸汽突破时间且提高了开采量。此外,在很多早期研究中应用的井网因素和单层砂岩模型并不能充分说明油田现场生产动态,利用大型非均质模型预测产量更加符合实际。非连续页岩允许原油从上部砂岩到下部砂岩大量泄油,因此上部含有的储量可能低于预测值,而下部的采收率明显增加。

Estimating the Operation Status of Steam Cracking Furnace Using Numerical Simulation with Combustion Models

An accurate and complete geometric model was constructed to simulate the combustion, flow and temperature environment in the radiant section of the steam cracking furnace. Simulation of flow and radiation status has utilized the standard k-ε model and P1 model. The finite-rate/eddy-dissipation (finite-rate/ED) combustion model and non-premixed combustion model were both used to simulate accurately the combustion and the operation status of the steam cracking furnace. Three different surfaces of the steam cracking furnace were obtained from the simulation, namely:the flue gas temperature field of the entrance surface in long flame burners, the central surface location of tubes, and the crossover section surface. Detailed information on the flue gas temperature and the mass concentration fraction of these different surfaces in the steam cracking furnace can also be obtained by the simulation. This paper analyzed and compared the simulation results with the two combustion models, estimated the operation status of the steam cracking furnace, and reported that the finite-rate/ED model is appropriate to simulate the steam cracking furnace by comparing key simulation data with actual test data. This work has also provided a theoretical basis for simulating and operating the steam cracking furnace.

Numerical Investigation on Effect of Vapor Split Ratio to Performance and Operability for Dividing Wall Column

Operability problem of dividing wall column (DWC) raised by vapor split was investigated by numerically analyzing four cases defined by different compositions of a three-component mixture. DWCs were firstly designed for each case by optimizing the vapor split to the two sides of the dividing wall, and then their feasibilities and total annual costs in operation were evaluated against different vapor split ratios. The analysis on the operability of the DWC for four cases was made based on two scenarios: (1) vapor split is shifted by the vapor resistance difference between the column sections in the two sides of the dividing wall and (2) the feed composition is changed. It was demonstrated that the positioning of the dividing wall and the decision on the vapor split may affect significantly the operability of a DWC.

Simulation Studies of the Hydrogen Production from Methanol Partial Oxidation Steam Reforming by a Tubular Packed-bed Catalytic Reactor

Hydrogen production by partial oxidation steam reforming of methanol over a Cu/ZnO/Al2 O3 catalyst has been paid more and more attention. The chemical equilibria involved in the methanol partial oxidation steam reforming reaction network such as methanol partial oxidation, methanol steam reforming, decomposition of methanol and water-gas shift reaction have been examined over the ranges of temperature 473-1073 K under normal pressure. Based on the detailed kinetics of these reactions over a Cu/ZnO/Al2O3 catalyst, and from the basic concept of the effectiveness factor, the intraparticle diffusion limitations were taken into account. The effectiveness factors for each reaction along the bed length were calculated. Then important results were offered for the simulation of this reaction process.

Fluid-solid coupling numerical simulation of charge process in variable-mass thermodynamic system

Abstract： A joint solution model of variabk：-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method （FEM）. The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7~105 W/（m2. K）. When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the： decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase.

液氨储罐泄漏危害程度及防范措施

以某企业30m3的液氨储罐发生事故为例,分析其存在的危险有害因素,并运用蒸汽云爆炸事故模拟分析方法定量地描述一个可能发生的事故对工厂、对厂内职工、对厂外居民甚至对环境造成危害的严重程度,并讨论相应的防范措施。

Dynamic simulation of drum level sloshing of heat recovery steam generator

Drum level sloshing is the latest discovery in the application of heat recovery steam generator (HRSG) in combined cycle, and shows certain negative influence on drum level controlling. In order to improve drum level controlling, influence factors on the drum level sloshing were investigated. Firstly, drum sub-modules were developed using the method of modularization modeling, and then the model of drum level sloshing was set up as well. Experiments were carried out on the experimental rig, and the model was validated using the obtained experimental results. Dynamic simulation was made based on the model to get a 3-D graph of drum level sloshing, which shows a vivid procedure of drum level sloshing. The effect of feed-water flow rate, main-steam flow rate and heating quantity on the drum level sloshing was analyzed. The simulation results indicate that the signals with frequency higher than 0.05 Hz are that of drum level sloshing, the signals with frequency of 0.0-0.05 Hz are that of drum level trendy and "false water level", and variation of the feed-water flow rates, main-steam flow rates and heating quantities can change the frequency of drum level sloshing, i.e., the frequency of sloshing increases with the increase of feed-water flow rate, or the decrease of the main-steam flow rate and the heating quantity. This research work is fundamental to improve signal-to-noise ratio of drum level signal and precise controlling of drum level.

Simulation analysis of static and dynamic characteristics of once-through steam generator in concentric annuli tube

The once-through steam generator (OTSG) in concentric annuli tube is a new type of steam generator which applies double side to transfer heat. The heat flux between the water of centric tube, outside annuli tube and that of annulus channel is assumed to be equal, and then the steam generator’s model is built by lumped parameters with moving boundary. In the basis of the built model, static and dynamic characteristics are analyzed. The static characteristics are proved by experiment results in a 19-tube once-through steam generator of Babcock & Wilcox. The characteristics that the lengths of three regions (subcooled region, nucleate boiling region, superheat region) change with power can be explained by theory analysis. The dynamic characteristics accord with the heat and hydraulics and the results of analysis according to the mechanism.

Heat calculation and numerical simulation in steam mining of permafrost gas hydrate

Steam mining method was injecting hot steam into the borehole to heat the hydrate strata at the same time of depressurization mining,which could promote further decomposition and expand mining areas of gas hydrate. Steam heat calculation would provide the basis for the design of heating device and the choice of the field test parameters. There were piping heat loss in the process of mining. The heat transfer of steam flowing in the pipe was steady,so the heat loss could be obtained easily by formula calculation. The power of stratum heating should be determined by numerical simulation for the process of heating was dynamic and the equations were usually nonlinear. The selected mining conditions were 500-millimeter mining radius,10 centigrade mining temperature and 180 centigrade steam temperature. Heat loss and best heating power,obtained by formula calculation and numerical simulation,were 21. 35 W/m and 20 kW.

Measurement of Viscosity Alteration for Emulsion and Numerical Simulation on Bitumen Production by SAGD Considering In-situ Emulsification

A thermal steam stimulation process, such as steam-assisted gravity drainage （SAGD）, induces water-in-oil emulsion of heavy oil or bitumen throughout the production. The present study investigated the effects of in-situ emulsification in the oil sands reservoir for SAGD process. The viscosities of water-in-oil emulsions produced were measured with respect to water-oil ratio （W/O）, shear rates, pressures and temperatures. The results therefore were employed to develop the numerical model of viscosity alteration. Numerical simulations of the SAGD bitumen production considering viscosity alteration were also carried out to investigate distribution characteristics of emulsion, water, and bitumen at steam chamber boundary and effects of in-situ emulsification on bitumen production behavior. With a model named SAGD-Emulsion Model, it was found that the net recovery factor of bitumen for this model is 5 to 10% higher than that of conventional SAGD simulation. Ultimately, it was found that the recovery factor of bitumen increased with W/O of emulsion generated in the reservoir since higher water content would invariably allow bitumen to flow at higher relative permeability, while the increase in viscosity merely delayed bitumen production.

Using hot-vapor bypass for pressure control in distillation columns

Distillation column control is widely explored in literature due to its complexity and importance in chemical and petrochemical industries. In this process, pressure represents one of the most important variables to be controlled. However, there are few studies about how pressure affects the dynamic behavior of distillation columns and most research on distillation column control involve direct manipulation of cooling fluid through the condenser. Nevertheless, such an approach demands constant changes in cooling fluid flowrates that are commonly by the order of tons per hour, which can be difficult to work or even unfeasible in a real plant. Furthermore, this strategy is usually avoided, as it can cause fouling and corrosion acceleration. The hot-vapor bypass strategy fits well as a solution for these issues, eliminating the need to dynamically manipulate cooling fluid flowrates in the condensation unit. This work presents the modeling and simulation of a conventional distillation column for the separation of water and ethanol, in which a comparative study between a conventional pressure control and a control using hot-vapor bypass was performed. The main results were obtained through dynamic simulations which considered various disturbances in the feed stream, and demonstrated superior performance by the hot-vapor bypass system over the usual scheme proposed in literature, while evaluating the lntegral Absolute Error （IAE） norm as the control performance index.

ATLAS MSLB Accident Analysis Using the SPACE Code

An integral effect test for a MSLB （main stem line break） was performed with the ATLAS （advanced thermal-hydraulic test loop for accident simulation） by KAERI （Korea Atomic Energy Research Institute）. A MSLB is defined as a pipe break in the main steam system. This data was used to validate the safety analysis code SPACE （safety and performance analysis code for nuclear power plants）. In the test, a double-ended guillotined break of the main steam line was simulated. After steady-state was reached, the test was started by opening the break simulation valves. With the start of the test, the pressure of the secondary system decreased rapidly, and reached the set-point of the LSGP （low steam generator pressure） signal. With the occurrence of the LSGP signal, the main steam isolation valves were closed. The SIPs （safety injection pumps） were started by the LPP （low pressurizer pressure） signal. In order to validate the SPACE code, a double-ended guillotine break of the main steam line at ATLAS was simulated. Most of the results show good agreement between the experiment data and the code calculated values.

Prediction of Boiler Drum Pressure and Steam Flow Rate Using Artificial Neural Network

Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lead to large simulation times, often exceeding transient real time. Artificial neural networks （ANNs） may be advantageous in this context, the main advantage being the speed of computation, the capability of generalizing from the few examples, robustness to noisy and partially incomplete data and the capability of performing empirical input-output mapping without complete knowledge of underlying physics. In this paper, the simulation of steam generator is considered as an example to show the potentialities of this tool. The data required for training and testing the ANN is taken from the steam generator at Abott Power Plant, Champaign （USA）. The total number of samples is 9600 which are taken at a sampling time of three seconds. The performance of boiler （drum pressure, steam flow rate） has been verified and tested using ANN, under the changes in fuel flow rate, air flow rate and load disturbance. Using ANN, input-output mapping is done and it is observed that ANN allows a good reproduction of non-linear behaviors of inputs and outputs.