Experimental Study of the Processes of Gas-Steam Pressurizer Insurge Transients

2020 ◽  
Author(s):  
Wang Bolong ◽  
Li Weihua ◽  
Jia Haijun ◽  
Li Jun ◽  
Hao Wentao
Keyword(s):  
Water Vapor ◽  
Liquid Phase ◽  
Nuclear Reactor ◽  
Influence Factors ◽  
Temperature Response ◽  
Experimental System ◽  
Pressure Control ◽  
Phase Region ◽  
Pressure Response ◽  
System Pressure

Abstract Small reactors have received more and more attention for their high safety, reliability, low power density, and short construction period. And the gas-steam pressurizer is widely used in small reactors due to its characteristics of simple structure, saves the heating and spray equipment, and prevents the coolant from boiling. The gas-steam pressurizer is a pressure control equipment for the reactor coolant system, and its characteristic of transient response is an important factor that affect operation stability of nuclear reactor systems. An experimental system was established to study the effect of pressure response for an insurge transient and influence factors were analyzed quantitatively. Experimental investigation shows that for the gas-steam pressurizer, the increase of coolant loading capacity (insurge) can cause system pressure rising. And the change of system pressure has much consistency with the change of liquid level and gas space temperature. The liquid phase exists temperature fluctuations and overall shows a downward trend during the insurge transient. And there exists a temperature gradient from bottom to top in the pressurizer liquid phase region during the insurge transient. The change of water vapor quantity curve is the oscillating curve during the transient and water vapor quantity is in a decreasing trend overall during the insurge transient. What’s more, the experiments also analyzed the pressure response and temperature response during the insurge transient.

scholarly journals Thermodynamics and Machine Learning Based Approaches for Vapor–Liquid–Liquid Phase Equilibria in n-Octane/Water, as a Naphtha–Water Surrogate in Water Blends

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 413
Author(s):  
Sandra Lopez-Zamora ◽  
Jeonghoon Kong ◽  
Salvador Escobedo ◽  
Hugo de Lasa
Keyword(s):  
Machine Learning ◽  
Liquid Phase ◽  
Phase Equilibria ◽  
Aspen Plus ◽  
Phase Region ◽  
Two Phase ◽  
Technical Literature ◽  
Phase Liquid ◽  
Liquid Vapor ◽  
Vapor Liquid

The prediction of phase equilibria for hydrocarbon/water blends in separators, is a subject of considerable importance for chemical processes. Despite its relevance, there are still pending questions. Among them, is the prediction of the correct number of phases. While a stability analysis using the Gibbs Free Energy of mixing and the NRTL model, provide a good understanding with calculation issues, when using HYSYS V9 and Aspen Plus V9 software, this shows that significant phase equilibrium uncertainties still exist. To clarify these matters, n-octane and water blends, are good surrogates of naphtha/water mixtures. Runs were developed in a CREC vapor–liquid (VL_ Cell operated with octane–water mixtures under dynamic conditions and used to establish the two-phase (liquid–vapor) and three phase (liquid–liquid–vapor) domains. Results obtained demonstrate that the two phase region (full solubility in the liquid phase) of n-octane in water at 100 °C is in the 10-4 mol fraction range, and it is larger than the 10-5 mol fraction predicted by Aspen Plus and the 10-7 mol fraction reported in the technical literature. Furthermore, and to provide an effective and accurate method for predicting the number of phases, a machine learning (ML) technique was implemented and successfully demonstrated, in the present study.

Experimental Research on Bonding Intensity of Iron Ores in the Sintering Process

2011 ◽  
Vol 391-392 ◽  
pp. 60-64
Author(s):  
Fang Yi Long ◽  
Sheng Li Wu ◽  
Juan Zhu ◽  
Yuan Du ◽  
Guo Liang Zhang
Keyword(s):  
South Africa ◽  
Liquid Phase ◽  
Experimental Research ◽  
Negative Correlation ◽  
Influence Factors ◽  
Iron Ores ◽  
Sintering Process ◽  
Different Types ◽  
Lower Porosity

The bonding intensity of four kinds of ores from Brazil, Australia and South Africa is researched in this study, and the influence factors are analyzed. The results show that, the ores of different types have apparently differences in bonding intensity, ores from Brazil and South Africa have high bonding intensity, while ores from Australia have low bonding intensity; The foundation of generation of effective liquid is adequate liquid phase fluidity and the lower porosity of core ore; The ratio of porosity of core ore and the index of liquid phase fluidity has negative correlation with the bonding intensity.

L1 Adaptive Control for Aircraft Air Management System Pressure-Regulating Bleed Valve

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
John Cooper ◽  
Chengyu Cao ◽  
Jiong Tang
Keyword(s):  
Management System ◽  
Control Valve ◽  
Pressure Control ◽  
Adaptive Controller ◽  
System Model ◽  
Flow Control Valve ◽  
L1 Adaptive Control ◽  
System Pressure ◽  
L1 Adaptive Controller ◽  
Linear Controllers

This paper presents an L1 adaptive controller for pressure control using an engine bleed valve in an aircraft air management system (AMS). The air management system is composed of two pressure-regulating bleed valves, a temperature control valve, a flow control valve, and a heat exchanger/precooler. Valve hysteresis due to backlash and dry friction is included in the system model. The nonlinearities involved in the system cause oscillations under linear controllers, which decrease component life. This paper is the unique in the consideration of these uncertainties for control design. This paper presents simulation results using the adaptive controller and compares them to those using a proportional–integral (PI) controller.

Experimental Investigation on Dependence of Decontamination Factor on Aerosol Number Concentration in Pool Scrubbing Under Normal Temperature and Pressure

2018 ◽  
Author(s):  
HaoMin Sun ◽  
Shinichi Machida ◽  
Yasuteru Sibamoto ◽  
Yuria Okagaki ◽  
Taisuke Yonomoto
Keyword(s):  
High Performance ◽  
Nuclear Reactor ◽  
Experimental System ◽  
Decontamination Factor ◽  
Number Concentration ◽  
Severe Accident ◽  
Measurement Instruments ◽  
Aerosol Number Concentration ◽  
Real Phenomenon ◽  
Validation Tests

During a severe accident of a nuclear reactor, radioactive aerosols may be released from degraded nuclear fuels. Pool scrubbing is one of the efficient filters with a high aerosol removal efficiency, in other words a high decontamination factor (DF). Because of its high performance, many pool scrubbing experiments have been performed and several pool scrubbing models have been proposed. In the existing pool scrubbing experiments, an experimental condition of aerosol number concentration was seldom taken into account. It is probably because DF is assumed to be independent of aerosol number concentration, at least, in the concentration where aerosol coagulation is limited. The existing pool scrubbing models also follow this assumption. In order to verify this assumption, we performed a pool scrubbing experiment with different aerosol number concentrations under the same boundary conditions. The test section is a transparent polycarbonate pipe with an inner diameter of 0.2 m. 0.5 μm SiO2 particles were used as aerosols. As a result, DF was increasing as decreasing the aerosol number concentration. In order to ensure a reliability of this result, three validation tests were performed with meticulous care. According to the results of these validation tests, it was indicated that DF dependence on the aerosol concentration was not because of our experimental system error including measurement instruments but a real phenomenon of the pool scrubbing.

Novel pressure control in supercritical fluid chromatography using a resistively heated restrictor

2009 ◽  
Vol 87 (3) ◽  
pp. 490-495 ◽  
Author(s):  
Jian Jun Li ◽  
Kevin B. Thurbide
Keyword(s):  
Supercritical Fluid ◽  
Supercritical Fluid Chromatography ◽  
Pressure Control ◽  
Detector Response ◽  
Operating Modes ◽  
System Pressure ◽  
Relative Standard ◽  
Flame Burner ◽  
Alternative Means ◽  
Column Pressure

An alternative means of independently controlling column pressure in supercritical fluid chromatography (SFC) by resistively heating the post-column restrictor is demonstrated. Compared to conventional block heating methods, resistive restrictor heating provides at least four times greater pressure programming rates and allows for much faster cooling times in between runs, thereby increasing sample throughput. When applying resistive restrictor heating in proximity to a flame ionization detector, the chromatographic baseline noise increases substantially and obscures peaks. However, adding about 100 mL/min of nitrogen into the flame burner essentially removes this noise and returns the detector response to normal. The analyte retention time in consecutive pressure gradient trials reproduces well with a minimal relative standard deviation of 0.36% (n = 3). The resistive restrictor heating technique presented is also found to be equally effective for either capillary or packed SFC operating modes. Results suggest that this method can potentially provide a simple, inexpensive, and convenient alternative to limited passive restrictors or more costly and complex backpressure regulators that are often used to maintain system pressure in supercritical fluid chromatography.

HETEROGENEOUS AZEOTROPIC DISTILLATION INVOLVING AN EMBEDDED TWO-LIQUID PHASE REGION

1995 ◽  
pp. 81-86
Author(s):  
Hassan S. Mumtaz ◽  
Grafton Corbett ◽  
Matthew Reagan ◽  
Warren D. Seider ◽  
Leonard A. Fabiano ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Azeotropic Distillation ◽  
Phase Region

scholarly journals A 1D RCE Study of Factors Affecting the Tropical Tropopause Layer and Surface Climate

2019 ◽  
Vol 32 (20) ◽  
pp. 6769-6782 ◽  
Author(s):  
Sally Dacie ◽  
Lukas Kluft ◽  
Hauke Schmidt ◽  
Bjorn Stevens ◽  
Stefan A. Buehler ◽  
...  
Keyword(s):  
Water Vapor ◽  
Climate Models ◽  
Temperature Response ◽  
Global Climate Models ◽  
Lapse Rate ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
Surface Climate ◽  
Ozone Profile ◽  
Convective Adjustment

Abstract There are discrepancies between global climate models regarding the evolution of the tropical tropopause layer (TTL) and also whether changes in ozone impact the surface under climate change. We use a 1D clear-sky radiative–convective equilibrium model to determine how a variety of factors can affect the TTL and how they influence surface climate. We develop a new method of convective adjustment, which relaxes the temperature profile toward the moist adiabat and allows for cooling above the level of neutral buoyancy. The TTL temperatures in our model are sensitive to CO2 concentration, ozone profile, the method of convective adjustment, and the upwelling velocity, which is used to calculate a dynamical cooling rate in the stratosphere. Moreover, the temperature response of the TTL to changes in each of the above factors sometimes depends on the others. The surface temperature response to changes in ozone and upwelling at and above the TTL is also strongly amplified by both stratospheric and tropospheric water vapor changes. With all these influencing factors, it is not surprising that global models disagree with regard to TTL structure and evolution and the influence of ozone changes on surface temperatures. On the other hand, the effect of doubling CO2 on the surface, including just radiative, water vapor, and lapse-rate feedbacks, is relatively robust to changes in convection, upwelling, or the applied ozone profile.

Pressure Control Characteristics Simulation Research of Electro-Hydraulic Proportional Variable Pump

2012 ◽  
Vol 232 ◽  
pp. 521-526
Author(s):  
Hui Wang ◽  
Zhuo Xu ◽  
Fan Long Meng
Keyword(s):  
Steady State ◽  
Structural Parameters ◽  
Pressure Control ◽  
Input Voltage ◽  
Core Diameter ◽  
Simulation Research ◽  
System Pressure ◽  
Simulating Analysis ◽  
System Output ◽  
Working Principle

Based on the theoretical analysis on working principle and motion of the electro-hydraulic proportional variable piston pump, it created and simulated the model in the AMESIM software. The influences of main structural parameters of variable pump on system output dynamic characteristics were revealed after simulating analysis results of pressure control characteristics. And the steady state output of system pressure is proportional to the input voltage of amplifier. The overshoot decreases with the increasing of input voltage, and the response get faster. The damping aperture of proportional reversing valve and core diameter of control plunger have a greater influence on the dynamic response of system.

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