scholarly journals CATHARE Assessment of Natural Circulation in the PKL Test Facility during Asymmetric Cooldown Transients

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Anis Bousbia Salah ◽  
Jacques Vlassenbroeck
Keyword(s):  
Natural Circulation ◽  
Test Facility ◽  
Steam Generators ◽  
Calculation Results ◽  
The Impact

Results of the CATHARE code calculations related to asymmetric cooldown tests in the PKL facility are presented. The test under consideration is the G2.1 experiment performed within the OECD/NEA PKL-2 project. It consists of carrying out a cooldown under natural circulation conditions in presence of two (out of four) emptied Steam Generators (SGs) and isolated on their secondary sides. The main goal of the current study is to assess the impact of a chosen cooldown strategy upon the occurrence of a Natural Circulation Interruption (NCI) in the inactive (i.e., noncooling) loops. For this purpose, three G2.1 test runs were investigated. The calculation results emphasize, mainly, the effect of the cooldown strategy, and the conditions that could lead to the occurrence of the NCI phenomenon.

Stability of Single-Phase Natural Circulation With Inverted U-Tube Steam Generators

1988 ◽  
Vol 110 (3) ◽  
pp. 735-742 ◽  
Author(s):  
J. Sanders
Keyword(s):  
Mathematical Model ◽  
Single Phase ◽  
Flow Direction ◽  
Natural Circulation ◽  
Boussinesq Equations ◽  
Test Facility ◽  
Normal Flow ◽  
Steam Generators ◽  
One Dimensional ◽  
Water Flows

For natural circulation it is shown that parallel flow in the tubes of an inverted U-tube steam generator can be, at certain power levels, unstable. A mathematical model, based on one-dimensional Oberbeck-Boussinesq equations, shows that stability can be attained if in some tubes the water flows backward, opposite to the normal flow direction. The results are compared to measurements obtained from the natural circulation test A2-77A in the LOBI-MOD2 integral system test facility.

scholarly journals Preliminary Assessment of Decay Heat Removal Systems in the ESFR-SMART Design: The Role of Natural Air Convection Around Steam Generators Outer Shells in Accidental Conditions

2020 ◽  
Author(s):  
Jeremy Bittan ◽  
Clement Bore ◽  
Joel Guidez
Keyword(s):  
Natural Circulation ◽  
Heat Removal ◽  
Steam Generators ◽  
Preliminary Assessment ◽  
Safety Criterion ◽  
Safety Level ◽  
Decay Heat ◽  
Air Convection ◽  
The Impact

Abstract In the frame of the ESFR-SMART European project, aiming at improving the safety level of the European Sodium cooled Fast Reactor (ESFR), this paper presents the preliminary assessment of decay heat removal systems in the ESFR-SMART design: the role of natural air convection around Steam Generators outer shells in accidental conditions. Both theoretical and CATHARE code (Thermal Hydraulics reference code) calculations are presented. The impact of an additional chimney at the top of each casing as well as running primary and secondary pumps on the heat removal capacity are equally evaluated. This paper shows that the evacuation of decay heat thanks to completely passive air natural circulation alone, in case of Fukushima like accident, should lead to temperatures of sodium in the reactor vessel temporarily exceeding the safety criterion of 650°C. The addition of chimneys increase the capacities but is not sufficient to evacuate the decay heat safely. If the primary and secondary side pumps are running, the safety criterion should be met.

Sail Aero-Structures: Studying Primary Load Paths and Distortion

2005 ◽  
Author(s):  
Robert Ranzenbach ◽  
Zhenlong Xu
Keyword(s):  
Aerodynamic Load ◽  
Element Analysis ◽  
Strain Behavior ◽  
Construction Methods ◽  
Load Paths ◽  
Calculation Results ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Field ◽  
The Impact ◽  
Primary Load

A method is described to conduct an integrated Fluid-Structure Interaction (FSI) simulation of sails that is based upon knowledge of the sail’s design shape geometry and membrane material properties. A Finite Element Analysis (FEA) of the sail structure and a Computational Fluid Dynamics (CFD) model of the aerodynamic field are combined and iteratively solved to compute the actual flying shape of the sail under aerodynamic load, the stress strain behavior of the sail membrane, the integrated aerodynamic forces produced by the sail such as driving force and heel moment, and the resulting loads on sheets, halyards, etc. An important contribution of this particular method is the incorporation of wrinkling phenomena into the FEA portion of the calculation. Results from a study of working sails for a 30’ MORC racing yacht designed by Nelson-Marek (NM) in the 1990’s are presented and discussed with particular emphasis on the variability of primary load paths with changing trim and sailing conditions as well as the impact of sail deformation in the direction of relatively small stresses that is often poorly addressed in many proprietary sail construction methods.

scholarly journals Gas Turbine Heat Recovery Steam Generators for Combined Cycles Natural or Forced Circulation Considerations

1988 ◽  
Author(s):  
Akber Pasha
Keyword(s):  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Power Plants ◽  
Natural Circulation ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Steam Generators ◽  
Forced Circulation ◽  
Gas Turbine Exhaust

In recent years the combined cycle has become a very attractive power plant arrangement because of its high cycle efficiency, short order-to-on-line time and flexibility in the sizing when compared to conventional steam power plants. However, optimization of the cycle and selection of combined cycle equipment has become more complex because the three major components, Gas Turbine, Heat Recovery Steam Generator and Steam Turbine, are often designed and built by different manufacturers. Heat Recovery Steam Generators are classified into two major categories — 1) Natural Circulation and 2) Forced Circulation. Both circulation designs have certain advantages, disadvantages and limitations. This paper analyzes various factors including; availability, start-up, gas turbine exhaust conditions, reliability, space requirements, etc., which are affected by the type of circulation and which in turn affect the design, price and performance of the Heat Recovery Steam Generator. Modern trends around the world are discussed and conclusions are drawn as to the best type of circulation for a Heat Recovery Steam Generator for combined cycle application.

Interaction of Shroud Leakage Flow and Main Flow in a Three-Stage LP Turbine

2003 ◽  
Vol 127 (4) ◽  
pp. 649-658 ◽  
Author(s):  
Jochen Gier ◽  
Bertram Stubert ◽  
Bernard Brouillet ◽  
Laurent de Vito
Keyword(s):  
Main Flow ◽  
Secondary Flows ◽  
Test Facility ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Jet Engines ◽  
Flow Interactions ◽  
Lp Turbine ◽  
The Impact ◽  
The Ideal

Endwall losses significantly contribute to the overall losses in modern turbomachinery, especially when aerodynamic airfoil load and pressure ratios are increased. In turbines with shrouded airfoils a large portion of these losses are generated by the leakage flow across the shroud clearance. Generally the related losses can be grouped into losses of the leakage flow itself and losses caused by the interaction with the main flow in subsequent airfoil rows. In order to reduce the impact of the leakage flow and shroud design related losses a thorough understanding of the leakage losses and especially of the losses connected to enhancing secondary flows and other main flow interactions has to be understood. Therefore, a three stage LP turbine typical for jet engines is being investigated. For the three-stage test turbine 3D Navier-Stokes computations are performed simulating the turbine including the entire shroud cavity geometry in comparison with computations in the ideal flow path. Numerical results compare favorably against measurements carried out at the high altitude test facility at Stuttgart University. The differences of the simulations with and without shroud cavities are analyzed for several points of operation and a very detailed quantitative loss breakdown is presented.

scholarly journals ON THE ISSUE OF DETERMINING THE CRITICAL CUTTING SPEED OF THE MECHANISM FOR FORMING AND TRIMMING THE FALSE EDGE OF THE DORNIER RAPIER LOOM

2021 ◽  
Vol 53 (3) ◽  
pp. 37-40
Author(s):  
Svitlana V. Bukina ◽  
Tatiana A. Sitnikova
Keyword(s):  
Rational Design ◽  
Mutual Influence ◽  
Cutting Speed ◽  
Design Parameters ◽  
Working Process ◽  
Forming Mechanism ◽  
Rational Design Parameters ◽  
Calculation Results ◽  
Knife Blade ◽  
The Impact

In this paper, an attempt is made to develop a method for determining the critical cutting speed of the threads of the false edge of the edge-forming mechanism of the weaving rapier machine. The proposed calculation method takes into account the impact nature of the cutting process at a critical speed, which allows taking into account the mutual influence of the parameters of the working process and more fully assess the mechanics of this process, in which the intensity of the cutting force and the value of the contact stress take the maximum value. The paper calculates the critical cutting speed for some of the main types of threads used and the parameters of the knife blade. The presented calculation results can be used to select rational design parameters of the knife blade, depending on the type of processed threads, when designing and researching new edge-forming mechanisms on looms.

scholarly journals THE ENGINEERING METHOD FOR UNIFYING GROUND FLOOR SLAB SETTLEMENTS

2021 ◽  
Vol 12 (2) ◽  
pp. 46-52
Author(s):  
Kęstutis Urbonas ◽  
Danutė Sližytė ◽  
Antanas Šapalas
Keyword(s):  
Engineering Method ◽  
Pile Foundations ◽  
Floor Slab ◽  
Ground Floor ◽  
Actual Behaviour ◽  
Industrial Buildings ◽  
Calculation Results ◽  
The Impact

For industrial buildings and logistics centres truck lifts are usually used. Therefore, there are special requirements for flatness tolerance of ground floor. The ground floor settlements differences in selected distances are limited. The article reviews the behaviour of soils and the importance of the actual behaviour assessment of soils during the design of floor slab on elastic subgrade. Particular attention is given to the behaviour of floor slab areas above pile foundations that support the building’s columns. Calculation results show the impact of subgrade stiffness on the behaviour of the floor slab, especially in areas above pile foundations, where the stiffness of subgrade is much higher. The article presents a solution for achieving the required level of settlements’ differences in areas where pile foundations for the building’s columns under the ground slab are used. The paper proposes an efficient engineering method to reduce ground slab settlements differences. The results of performed calculations confirm the efficiency of presented method.

Progress of the 40 MW-Class Advanced Humid Air Turbine Tests

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Manabu Yagi ◽  
Hidefumi Araki ◽  
Hisato Tagawa ◽  
Tomomi Koganezawa ◽  
Chihiro Myoren ◽  
...  
Keyword(s):  
Metal Surface ◽  
Control Method ◽  
Cooling System ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Test Facility ◽  
Humid Air ◽  
Air Turbine ◽  
Calculation Results ◽  
Flow Compressor

A 40 MW-class test facility has been constructed to verify practicability of applying the advanced humid air turbine (AHAT) system to a heavy-duty gas turbine. Verification tests have been carried out from January 2012, and interaction effects between the key components were established. First, water atomization cooling (WAC) was confirmed to contribute to both increased mass flow rate and pressure ratio for the axial-flow compressor. The good agreement between measured and calculated temperatures at the compressor discharge was also confirmed. These results demonstrated the accuracy of the developed prediction model for the WAC. Second, a control method that realized both flame stability and low nitrogen oxides (NOx) emissions was verified. Although the power output and air humidity were lower than the rated values, NOx concentration was about 10 ppm. Finally, a hybrid nozzle cooling system, which utilized both compressor discharged air and humid air, was developed and tested. The metal surface temperatures of the first stage nozzles were measured, and they were kept under the permissible metal temperature. The measured temperatures on the metal surface reasonably corresponded with calculation results.

ON THE DEVELOPMENT OF TESTING FACILITIES FOR THE SCIENTIFIC TEST-ING CENTER OF THE ROCKET AND SPACE INDUSTRY FOR DEVELOPMENTAL TESTING OF ADVANCED CRYOGENIC PROPULSION SYSTEMS

2021 ◽  
pp. 88-97
Author(s):  
Nikolay P. SIZYAKOV ◽  
Igor A. YURIEV ◽  
Ayvengo G. GALEEV
Keyword(s):  
Propulsion System ◽  
Test Facility ◽  
Launch Vehicles ◽  
Propulsion Systems ◽  
Safety Measures ◽  
Experimental Development ◽  
Space Industry ◽  
Calculation Results ◽  
Testing Center ◽  
Scientific Testing

The paper provides a review of materials on the development of testing facilities in the Scientific Testing Center of the Rocket and Space Industry and the issues involved in raising the efficiency and safety of experimental development of advanced cryogenic propulsion systems for launch vehicles intended for exploration of the near and deep space. It shows that the most dangerous tests are those that are conducted on engines and propulsion systems that use oxygen, methane and hydrogen as propellant components. They may involve containment failure in the propellant system in off-nominal situations — emergency releases of propellant components, explosions and fires. It provides calculation results for overpressure in the shock-wave front depending on the mass of the released hydrogen and the factor of its contribution to the explosion. It formulates special and additional safety measures for engine and propulsion system tests in a test facility. Key words: test facility (test stand), propulsion system, safety, off-nominal situation, cryogenic propellant components.

Experimental Study on the Effect of Clocking on the Propagation of Inflow Pressure Distortions in a Low Pressure Turbine Stage

2020 ◽  
Author(s):  
L. Simonassi ◽  
M. Zenz ◽  
P. Bruckner ◽  
S. Pramstrahler ◽  
F. Heitmeir ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Total Pressure ◽  
Low Pressure ◽  
Vibration Characteristics ◽  
Test Facility ◽  
Turbine Stage ◽  
Rotor Vibration ◽  
Low Pressure Turbine ◽  
The Impact

Abstract The design of modern aero engines enhances the interaction between components and facilitates the propagation of circumferential distortions of total pressure and temperature. As a consequence, the inlet conditions of a real turbine have significant spatial non-uniformities, which have direct consequences on both its aerodynamic and vibration characteristics. This work presents the results of an experimental study on the effects of different inlet total pressure distortion-stator clocking positions on the propagation of total pressure inflow disturbances through a low pressure turbine stage, with a particular focus on both the aerodynamic and aeroelastic performance. Measurements at a stable engine relevant operating condition and during transient operation were carried out in a one and a half stage subsonic turbine test facility at the Institute of Thermal Turbomachinery and Machine Dynamics at Graz University of Technology. A localised total pressure distortion was generated upstream of the stage in three different azimuthal positions relative to the stator vanes. The locations were chosen in order to align the distortion directly with a vane leading edge, suction side and pressure side. Additionally, a setup with clean inflow was used as reference. Steady and unsteady aerodynamic measurements were taken downstream of the investigated stage by means of a five-hole-probe (5HP) and a fast response aerodynamic pressure probe (FRAPP) respectively. Strain gauges applied on different blades were used in combination with a telemetry system to acquire the rotor vibration data. The aerodynamic interactions between the stator and rotor rows and the circumferential perturbation were studied through the identification of the main structures constituting the flow field. This showed that the steady and unsteady alterations created by the distortion in the flow field lead to modifications of the rotor vibration characteristics. Moreover, the importance of the impact that the pressure distortion azimuthal position has on the LPT stage aerodynamics and vibrations was highlighted.

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