Results of experimental studies of changes in the level and heating of the main condensate in mixing-type LPH

2021 ◽  
Vol 13 (4) ◽  
pp. 290-295
Author(s):  
E. A. Sukhorukova ◽  
N. N. Trifonov ◽  
S. P. Kolpakov
Keyword(s):  
Water Distribution ◽  
Technical Problem ◽  
Experimental Studies ◽  
Check Valve ◽  
Normal Operation ◽  
Steam Turbines ◽  
Manufacturing Defects ◽  
Water Chamber ◽  
Heating Section ◽  
Hydraulic Shocks

In the thermal circuits of domestic steam turbines, mixing-type low-pressure heaters (LPH) with free-flow jet water distribution and counter-flow of water and steam are widely used. The choice of the counterflow variant of the media movement ensures the most efficient heat transfer. However, the technical problem of ensuring reliable operation of LPH in the entire range of design loads of TPP and NPP power units is still relevant.During the commissioning and operation of mixing-type LPH in 800÷1200 MW turbines of TPP and NPP, the presence of metal knocks in the zone of the check valve, hydraulic shocks in the heating section were revealed. A priori, these phenomena indicated design flaws in LPH or manufacturing defects in their production. Research carried out by NPO CKTI specialists showed that periodic hydraulic shocks in the heating section and metal knocks occur as a result of uneven distribution around the circumference of the main condensate and steam supply. This leads to a breakdown of the check valve and the destruction of perforated plates and off-design heating of water in the volume of the annular LPH water chamber. To clarify the causes of the damage, develop recommendations for the reconstruction of the apparatus and further account for the design, two series of experimental studies were carried out on mixing-type heaters of 800 MW turbine units PNSV-2000-1 and PNSV-2000-2 manufactured at PJSC Krasny Kotelshchik. The purpose of the experimental studies was to determine the change in the water level in the water chamber and the heating of the main condensate in the elements of the heating compartment during normal operation of the power unit at loads of 400÷850 MW. Based on the results of the research, the method for calculating the mixing-type LPH has been refined, taking into account the revealed non-uniformity of water heating in the water chamber, recommendations for their reconstruction have been developed and implemented. 

scholarly journals PLANNING OF EXPERIMENTAL STUDIES OF THE "FOUNDATION-BASE" SYSTEM IN CASE OF SUDDEN OVERLOADS

2020 ◽  
pp. 5-12
Author(s):  
I. M. Diakov ◽  
M. I. Diakov ◽  
B. Y. Barykin
Keyword(s):  
Experimental Studies ◽  
Normal Operation ◽  
Base System ◽  
System Operation ◽  
Foundation Soil ◽  
Soil System ◽  
Emergency Situations ◽  
Foundation Base ◽  
Sudden Loading ◽  
Experimental And Theoretical Studies

The relevance of experimental and theoretical studies of the work of the foundation-foundation system in sudden burdens is justified. It was established that sudden loads can occur both in emergency situations and in the course of normal operation. The main criterion of sudden loading is the rate of additional or main (operational) loading, which is higher than the rate of stress redistribution in the base. In order to identify the main features of the foundation-foundation system and plan further studies, the results of preliminary experiments of the interaction of foundations with the soil base during sudden loads were analyzed. The accepted method of experimental research is described, the characteristics of the models of foundations and the power system used for testing are given. Some features of "foundation-soil" system operation in case of sudden loading are defined. Based on the conducted experiments, the need for further study of the foundation-foundation system in case of sudden loading was substantiated and the experiments were planned.

scholarly journals On the Enhanced Accuracy of Kinetic Curve Building in Supercritical Fluid Extraction from Aroma Plants Using a New 3D-Printed Extract Collection Device

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2008
Author(s):  
Denis Prokopchuk ◽  
Oleg Pokrovskiy
Keyword(s):  
Supercritical Fluid Extraction ◽  
Supercritical Fluid ◽  
Mass Measurement ◽  
Technical Problem ◽  
Kinetic Curve ◽  
Check Valve ◽  
Cyclone Separator ◽  
Sample Collection ◽  
Fluid Extraction ◽  
New Device

Accurate collection of extracted material represents a technical problem in supercritical fluid extraction because trapping should be performed in severe conditions of rapidly moving and freezing expanded fluid. We have developed a simple device for effective sample collection in analytical-scale supercritical fluid extraction. The device consists of a cyclone separator equipped with a spray trap and a heated check valve. The cyclone separator and spray trap are manufactured from a light polymer via 3D printing and are quick-detachable, which encourages its use in applications where mass yield measurements are required. The device was compared to a standard tubing-and-vial approach in the task of building kinetic curves for the extraction from two aroma plants, namely, laurel and rosemary. The new device showed almost two-fold increase in extraction trapping, most probably due to better collection of volatile compounds. A curious effect of the number of mass measurement points per curve on apparent yield was observed. An increase in the number of points led to an increase in yield, probably due to the effect of the static–dynamic extract regime posed by the manner in which the device is used.

Experimental Study on Natural Circulation in a Lead Bismuth Eutectic Loop

2017 ◽  
Author(s):  
Leitai Shi ◽  
Guanghui Su ◽  
Tan Bing ◽  
Ronghua Chen ◽  
Wenxi Tian ◽  
...  
Keyword(s):  
Temperature Difference ◽  
Natural Circulation ◽  
Power Level ◽  
Transfer Characteristic ◽  
Normal Operation ◽  
Test Facility ◽  
Maximum Temperature ◽  
Convection Flow ◽  
Operation Temperature ◽  
Heating Section

In order to investigate the thermal-hydraulic characteristics of LBE in Accelerator Driven System (ADS), the Natural Circulation Capability Loop (NCCL) test facility was designed and constructed at Xi’An Jiaotong university in 2015. NCCL is a middle-scale experimental loop designed for investigating the natural circulation capacity, gas-lift pump enhancing circulation capacity and heat-transfer characteristic of LBE. For the natural circulation capability experiment, the loop is filled with argon gas at 0.2 MPa before filling LBE from store tank. The maximum temperature of LBE is 500 C°, while the normal operation temperature was maintained at 400 C°. In this paper, the LBE natural circulation characteristics were investigated with experiments in NCCL test facility. The study includes measurements on start-up of natural circulation and capability of natural circulation. Significant natural convection flow was observed in the experiments. It was found that the natural circulation was quickly established and stabilized due to LBE high thermal expansion property. It took only a few minutes to have a stable natural circulation prevailing from cold conditions. At the same time, the temperature difference between heating section and cooling section increase quickly and reach to the maximum value. And in the range of 10 minutes, a steady circulation can be performed. The natural circulation flowrate depends on the loop resistance, and the temperature difference between the hot leg and the cold leg, as determined by the power level and the heat sink capacity. The experiments show that the maximum flowrate for the natural circulation is 0∼0.81 kg/s.

scholarly journals RESEARCH FEATURES OF AEROELASTIC OSCILLATIONS OF UNMANNED AERIAL VEHICLES WITH ELECTRIC ACTUATOR OF RUDDERS

2018 ◽  
Vol 21 (4) ◽  
pp. 73-83
Author(s):  
A. V. Bykov ◽  
S. G. Parafes ◽  
V. I. Smyslov
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Modular Design ◽  
Experimental Studies ◽  
Operation Time ◽  
Gear Ratio ◽  
Elastic Structure ◽  
Normal Operation ◽  
Technical Problems ◽  
Aerial Vehicles ◽  
Almost All

Designing a modern flight vehicle is associated with the need to solve many scientific and technical problems. These tasks include the prevention of insecure self-oscillations in flight, taking into account the elasticity of the structure. These problems relate to dynamic aeroelasticity, a science that examines the interaction of an elastic structure (at its oscillation) with an air flow. Maneuverable unmanned aerial vehicles (UAVs) are considered. Since UAVs are essentially not used without an automatic control system (ACS), its presence must be taken into account when considering the vibrations of an elastic structure in flight. The influence of the elasticity of UAV design on the operation of ACS in flight is manifested in the possibility of self-oscillations in the loop "elastic UAV – ACS". Self-oscillations lead to disruption of normal operation of the onboard equipment or its failure. The complexity of the problem requires its consideration at almost all stages of UAV’s development, including the creation of a prototype and testing. The computational and experimental studies of the characteristics of elastic oscillations in the UAV flight of the cross-shaped scheme are considered. The features of these UAVs (options with a modular design, the nonlinearity of the airframe, rudders, ACS, and others) due to a significant amount of testing that is the basis for the calculations. Electric actuators have a small continuous operation time, and resource use, there are gearboxes with a large gear ratio and backlashes. This determines the dependence of the rotation rigidity of the rudders on the amplitude and frequency, as well as a significant increase in the total moments of inertia. The technique of bench experiment with obtaining data to assess the boundaries of the flutter and the boundaries of the stability of the loop "elastic UAV – ACS" is given. The questions of improvement of the stabilization system of UAV required for the study of its stability at frequencies of elastic oscillations are considered, as well as the evaluation of the limiting cycles of self-oscillations is given.

scholarly journals Justification of nonstandard geometry of exhaust duct of steam turbine low pressure cylinder: case study of K-300-240-2 LMZ

Vestnik IGEU ◽  
2020 ◽  
pp. 5-13
Author(s):  
A.D. Brekotkina ◽  
E.Yu. Semakina ◽  
P.N. Brodnev ◽  
V.A. Chernikov
Keyword(s):  
Vector Fields ◽  
Experimental Studies ◽  
Low Pressure ◽  
Aerodynamic Characteristics ◽  
Steam Turbines ◽  
New Approach ◽  
Exhaust Duct ◽  
Pressure Cylinder ◽  
Sst Turbulence Model

Presently the losses of kinetic energy in the exhaust duct of low-pressure cylinder are considerable, since numerous spacer bars and directing plates are located inside. A fundamentally new approach is required to design the exhaust duct of LPC without internal elements in water passage and providing the decline of losses due to improvement of the diffuser form and collapsible chamber. The flow modeling in the considered exhaust duct design was carried out by the numerical RANS method with the SST turbulence model. To validate the CFD model, the results of the previous experimental studies of the basic design model were used. The comparison of the integral aerodynamic characteristics of the exhaust duct was carried out. For the basic variant of the exhaust duct, the variant without internal elements, and also for the variant without internal elements and with new geometry of the collapsible chamber, according to the results of the numeral experiment, distribution of pressure and vector fields of speeds in the exhaust nozzle are received and the integral parameters of the exhaust duct are defined. Advantage of the integral descriptions of the exhaust duct without internal elements and with a new form of collapsible chamber is proven. They are the coefficient of internal losses of the exhaust duct, the coefficient of kinematics unevenness of the stream, and the coefficient of repressuring in an axial-radial diffuser. It has been established that a new approach of geometry of the exhaust duct of LPC provides the improvement of their aerodynamic qualities when designing new high-powered steam-turbines to operate in TPP and NPP. The advantage of losses decline of energy in the exhaust duct is multiple, because the number of LPC streams in modern seam-turbines can amount up to eight.

scholarly journals Heating modes and design optimization of cogeneration steam turbines of powerful units of combined heat and power plant

Energetika ◽  
2019 ◽  
Vol 65 (1) ◽  
Author(s):  
Andrey Rusanov ◽  
Aleksandr Shubenko ◽  
Oleksandr Senetskyi ◽  
Olga Babenko ◽  
Roman Rusanov
Keyword(s):  
Steam Turbine ◽  
Turbulent Flows ◽  
Software Package ◽  
Technical Problem ◽  
Three Dimensional ◽  
Software Systems ◽  
Steam Turbines ◽  
Rational Distribution ◽  
Flow Part ◽  
Numerical Research

An important scientific and technical problem of increasing the efficiency of CHP steam turbine units through the optimization of their operation modes and the creation of new highly efficient flow parts of cogenerating turbines is solved. Solutions to the problem of rational distribution of heat loads between the network heaters of cogeneration turbines during the heating period are presented. The calculations were performed using the software package SCAT which was developed in IPMach NAS of Ukraine. The carrying out of calculations of three-dimensional turbulent flows in flow parts of turbines using modern software systems is an effective direction of increased efficiency of power equipment. For the numerical research of three-dimensional currents, steam in the flow part of the steam turbine software package IPMFlow which is developed in IPMach NAS of Ukraine is used. With the use of software package IPMFlow, the researches of three-dimensional currents steam in the flow part of the medium pressure cylinder of the steam turbine of series T-100-130 are carried, which showed the feasibility of optimizing the geometry of the flow part in order to improve gas-dynamic characteristics of blades apparatuses.

Software Enabled Variable Displacement Pumps: Experimental Studies

2006 ◽  
Author(s):  
Michael B. Rannow ◽  
Haink C. Tu ◽  
Perry Y. Li ◽  
Thomas R. Chase
Keyword(s):  
Experimental Studies ◽  
Check Valve ◽  
Design Parameters ◽  
Duty Ratio ◽  
System Response ◽  
Experimental Apparatus ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Valve Control ◽  
Variable Displacement Pumps

The majority of hydraulic systems are controlled using a metering valve or the use of variable displacement pumps. Metering valve control is compact and has a high control bandwidth, but it is energy inefficient due to throttling losses. Variable displacement pumps are far more efficient as the pump only produces the required flow, but comes with the cost of additional bulk, sluggish response, and added cost. In a previous paper [1], a hydromechanical analog of an electronic switch-mode power supply was proposed to create the functional equivalent of a variable displacement pump. This approach combines a fixed displacement pump with a pulse-width-modulated (PWM) on/off valve, a check valve, and an accumulator. The effective pump displacement can be varied by adjusting the PWM duty ratio. Since on/off valves exhibit low loss when fully open or fully closed, the proposed system is potentially more energy efficient than metering valve control, while achieving this efficiency without many of the shortcomings of traditional variable displacement pumps. The system also allows for a host of programmable features that can be implemented via control of the PWM duty ratio. This paper presents initial experimental validation of the concept as well as an investigation of the system efficiency. The experimental apparatus was built using available off-the-shelf components and uses a linear proportional spindle valve as the PWM valve. Experimental results confirm that the proposed approach can achieve variable control function more efficiently than a valve controlled system, and that by increasing the PWM frequency and adding closed-loop control can decrease system response times and of the output ripple magnitude. Sources of inefficiency and their contributions are also investigated via modeling, simulation and are validated by experiments. These indicate design parameters for improving inefficiency.

scholarly journals Estimation of usage efficiency of freon-steam turbines in mine energy complexes

2020 ◽  
Vol 168 ◽  
pp. 00048
Author(s):  
Mykhailo Kirsanov ◽  
Inna Diakun ◽  
Vitalii Ruban ◽  
Viktor Skosyriev ◽  
Oleksandr Zhevzhyk
Keyword(s):  
Equations Of State ◽  
Waste Heat ◽  
Technical Problem ◽  
Energy Conversion Efficiency ◽  
Energy Utilization ◽  
Operating Efficiency ◽  
Steam Turbines ◽  
Working Fluids ◽  
Potential Sources ◽  
Efficiency Estimation

Increase of operating efficiency of mine energy complexes is an actual scientific and technical problem. Systems that utilize energy of low-potential sources and have freon-steam turbines are suggested to be included in mine energy complexes. Principles of selection of freons as working fluids in energy systems are suggested in the paper. Usage of some thermal equations of state for defining thermal and physical properties of freons is analyzed. Equation of isentropic process for the thermal Redlich–Kwong equation of state is obtained. Calculation of energy efficiency of a system with a freon-steam turbine for selected variants of usage of working fluids is performed. A calculation method of thermodynamic parameters that are necessary for energy conversion efficiency estimation of specific freons in a system of useful utilization of energy is developed. Analysis of results indicates that usage of ozone-safe and fire-safe freons in energy utilization systems of low-potential sources with a possibility of utilization of additional waste heat, which was not used in the past, allows increasing the operating efficiency of mine energy complexes.

scholarly journals Pumping Station Design in Water Distribution Networks Considering the Optimal Flow Distribution between Sources and Capital and Operating Costs

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3098
Author(s):  
Jimmy H. Gutiérrez-Bahamondes ◽  
Daniel Mora-Meliá ◽  
Pedro L. Iglesias-Rey ◽  
F. Javier Martínez-Solano ◽  
Yamisleydi Salgueiro
Keyword(s):  
Optimization Model ◽  
Water Distribution ◽  
Flow Distribution ◽  
Distribution Networks ◽  
Operating Conditions ◽  
Water Distribution Networks ◽  
Operating Costs ◽  
Normal Operation ◽  
Optimal Flow ◽  
Pumping Stations

The investment and operating costs of pumping stations in drinking water distribution networks are some of the highest public costs in urban sectors. Generally, these systems are designed based on extreme scenarios. However, in periods of normal operation, extra energy is produced, thereby generating excess costs. To avoid this problem, this work presents a new methodology for the design of pumping stations. The proposed technique is based on the use of a setpoint curve to optimize the operating and investment costs of a station simultaneously. According to this purpose, a novel mathematical optimization model is developed. The solution output by the model includes the selection of the pumps, the dimensions of pipelines, and the optimal flow distribution among all water sources for a given network. To demonstrate the advantages of using this technique, a case study network is presented. A pseudo-genetic algorithm (PGA) is implemented to resolve the optimization model. Finally, the obtained results show that it is possible to determine the full design and operating conditions required to achieve the lowest cost in a multiple pump station network.

scholarly journals Bowels of the earth – natural physical-chemical reactor: is the search for natural methane a fundamental science or a technical problem?

2019 ◽  
Vol 4 (181) ◽  
pp. 104-115
Author(s):  
Yosyp SVOREN
Keyword(s):  
Oil And Gas ◽  
Isotope Composition ◽  
New Technology ◽  
Technical Problem ◽  
Experimental Studies ◽  
Chemical Reactor ◽  
Local Area ◽  
Scientific Basis ◽  
Hydrocarbon Synthesis ◽  
Physical Chemical

It is shown that the hypothesis of organic origin of hydrocarbons doesn’t respond to the presence of a dominant concentration of methane in sediments, deposits, “shale’ series and so on, hence prospecting and exploration for hydrocarbon deposits in them are conducted in most cases intuitively, but not on the fundamental scientific basis. Experimental studies based on the heating of slightly modified organic matter (peat) show that up to 200 °C in the process of its decomposition the following gases were delivered (vol. %): CO2 = 49.5; H2O = 49.3; CH4, C2H6, C3H8, N2, H2, SO2, H2S within 1.2 % in total. It is confirmed that there is no coal methane, there is no shale gas-methane, but there is methane of one genesis with slightly different isotope composition of carbon, but synthesized according to the same mechanism in the high-thermobaric processes that after migration into the earth’s crust accumulated in the form of deposits in cavities of coal seams, terrigenous units, sandstones and so on. Prospecting for pool-deposits of hydrocarbons should be carried out in conformity with developed “new technology of determination of prospects for oil and gas presence in the local area”, “physical-chemical model of synthesis of hydrocarbons and the way of geochemical searching for their occurrences”, “new theory of hydrocarbon synthesis and genesis in the earth’s lithosphere: abiogenic-biogenic dualism”.

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