scholarly journals Development of Automatic Equipment for Washing and Nondestructive Inspection of Stud Bolt

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
H. S. Kwak
Keyword(s):  
High Pressures ◽  
Nondestructive Inspection ◽  
Operating Conditions ◽  
Energy Utilization ◽  
Steam Turbines ◽  
Cleaning Efficiency ◽  
Automatic Equipment ◽  
Element Analysis ◽  
Pressure Steam ◽  
Screw Threads

Low-pressure steam turbines in a power plant are required to operate at high temperatures and under high pressures to achieve better energy utilization and better performance. Higher operating temperatures accelerate the rate of oxidation and sludge formation, so the steam turbine is periodically inspected including strict examination of the stud bolts, and it is necessary to clean the bolts by removing sludge from their screw threads. In the conventional cleaning process, the sludge has been removed by manual cleaning, which is labor-intensive and time-consuming. Therefore, this study developed automatic equipment for washing and nondestructive inspection of stud bolts using theoretical analysis and finite element analysis (FEA). An optimal clamp load to prevent sliding of the roller was calculated, and a structural analysis of the equipment under operating conditions was conducted. An optimal washing condition to maximize cleaning efficiency was proposed using design of the experiment and verified by performing washing test of prototype.

Bottoming Cycle Performance in Large Size Combined Cycle Power Plants—Part A: Health Monitoring System

2009 ◽  
Author(s):  
Silvio Cafaro ◽  
Alberto Traverso ◽  
Aristide F. Massardo ◽  
Roberto Bittarello
Keyword(s):  
Heat Exchanger ◽  
Steam Turbine ◽  
Measurement Errors ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Direct Result ◽  
Steam Turbines ◽  
Large Size ◽  
Performance Indexes ◽  
Pressure Steam

This research is focused on the monitoring and diagnostic of the bottoming cycle (BC) of a large size combined cycle, composed by a three pressure level HRSG (Heat Recovery Steam Generator), a three expansion level steam turbine and auxiliary pumps. An original Matlab software was developed, which is composed by two parts: the first calculates HRSG performance, while the second is focused on the calculation of the steam turbines performance, at different power plant operating conditions. In the first part a complete HRSG performance analysis is carried out: it consists of the calculation of each heat exchanger performance and health. The direct result of this analysis is the definition of Non Dimensional Performance Indexes (NDPI) for each heat exchanger, which define the instant degradation of each component, through the comparison between the “actual” and the “expected” effectiveness. The second part calculates steam turbines performance. Two NDPIs are defined: one referred to the high pressure steam turbine and the other referred to the middle-low pressure steam turbine. The performance indexes are calculated comparing the actual expansion efficiency with the expected one. The NDPI previously defined will be used to monitor plant degradation, to support plant maintenance, and to assist on-line troubleshooting. Each performance parameter is coupled with an accuracy factor, which allows to determine the best parameters to be monitored and to define the related tolerance due to measurement errors. The methodology developed has been successfully applied to historical logged data (2 years) of an existing large size (400 MW) combined cycle, demonstrating the capabilities in estimating the degradation of the BC performance throughout plant life.

scholarly journals A Model for Liquid Films in Steam Turbines and Preliminary Validations

2016 ◽  
Author(s):  
Amélie Simon ◽  
Meryem Marcelet ◽  
Jean-Marc Hérard ◽  
Jean-Marc Dorey ◽  
Michel Lance
Keyword(s):  
Mass Transfer ◽  
Shallow Water Equations ◽  
Liquid Films ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Power Losses ◽  
Pressure Surface ◽  
Falling Liquid Film ◽  
Pressure Steam ◽  
Droplet Impacts

Liquid films in steam turbines, present in usual operating conditions, play a large but poorly understood part in the wetness-born troubles (power losses and erosion). More knowledge is needed to estimate their impacts and lessen their effects. The aim of this paper is to propose and verify a model to predict these liquid films. This model is based on modified Shallow-Water equations (integral formulation). It takes into account inertia, mass transfer, gravity, gas and wall frictions, pressure, surface tension, droplet impacts, rotational effects and is unsteady. A 2D code has been developed to implement this model. A part of the model has been verified with analytical solutions (Riemann problems and inclined lake at rest), has been confronted with the linear stability of falling liquid film and has been validated with the experiment of Hammitt et al. [1] which involves a sheared film under low-pressure steam turbine conditions.

Numerical and Experimental Aerodynamic Investigation of a Low Pressure Steam Turbine Module

2019 ◽  
Author(s):  
Juri Bellucci ◽  
Lorenzo Peruzzi ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
Nicola Maceli
Keyword(s):  
Steam Turbine ◽  
Three Dimensional ◽  
Low Pressure ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Experimental Results ◽  
Steam Turbines ◽  
Performance Curves ◽  
Pressure Steam ◽  
Cfd Analyses

Abstract This work aims to deepen the understanding of the aerodynamic behavior and the performance of a low pressure steam turbine module. Numerical and experimental results obtained on a three-stage low pressure steam turbine (LPT) module are presented. The selected geometry is representative of the state-of-the-art of low pressure sections for small steam turbines. The test vehicle was designed and operated in different operating conditions with dry and wet steam. Different types of measurements are performed for the global performance estimation of the whole turbine and for the detailed analysis of the flow field. Steady and unsteady CFD analyses have been performed by means of viscous, three-dimensional simulations adopting a real gas, equilibrium steam model. Measured inlet/outlet boundary conditions are used for the computations. The fidelity of the computational setup is proven by comparing computational and experimental results. Main performance curves and span-wise distributions show a good agreement in terms of both shape of curves/distributions and absolute values. Finally, an attempt is done to point out where losses are generated and the physical mechanisms involved are investigated and discussed in details.

Failure Diagnosis in Rotory Dynamic Systems Based on Finite Element Prediction Model

2003 ◽  
Author(s):  
Amir Shirkhodaie ◽  
Julian Blair ◽  
Kemba Heard
Keyword(s):  
Finite Element ◽  
Research Effort ◽  
Rotating Machinery ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Element Analysis ◽  
Operation Conditions ◽  
Technological Advances ◽  
Machinery Diagnostics ◽  
Abnormal Operating Conditions

Machinery such as steam turbines, compressors, and generators are rotating machines. Over the years these machines have become very complex, due to the increased need for higher speed rotating machinery. Overtime these machines develop excessive dynamic stresses if they are ran at speeds near to their natural frequencies or under abnormal operating conditions. Many technological advances in the aerospace and automotive industries can be held accountable for these faster speeds. Currently, machinery diagnostics is being used to monitor rotating machinery and determine their condition while in operation. To determine how a system will behave under certain operation conditions, a physics-based model of the system can be modeled and analyzed using finite element analysis. These results will provide stress, deformation, flexibility, stiffness, and vibration characteristics of the system. These results can show where the critical points are on the system and how the system’s load is distributed. By using finite element techniques engineers can simulate the behavior of the system under different loading conditions, which can justify the selection of a particular design alternative, and ultimately save time and money. This paper discusses our technical approach used to develop a physics-based model of a rotor dynamic system and discusses results of this research effort.

Design Aspects of a Cardiac Action Hydraulic Pump

2015 ◽  
Author(s):  
Mohamed Elgamil ◽  
Khaled Mostafa ◽  
Marwan El-Husseiny ◽  
Saad Kassem
Keyword(s):  
High Performance ◽  
High Pressures ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Hydraulic Pump ◽  
Element Analysis ◽  
Flow Rates ◽  
Control Chamber ◽  
Chamber Volume ◽  
Cardiac Action

This paper presents some design aspects of a high pressure cardiac action hydraulic pump consisting of several pumping heads. Each head has a set of followers that completely encircle a cam. The followers separate a pumping chamber, formed between the cam and the followers, from a control chamber existing outside the followers. With the cam rotation the followers move outwards and inwards with respect to the cam, causing the pumping chamber volume to increase and decrease to suck and pump oil. The pump geometric volume can be controlled by controlling the stroke of the followers through the control of the oil volume in the control chamber. Three different methods are proposed to transmit the motion from the cam to the followers. In the first method the followers are in direct contact with the cam, while in the second intermediate cylindrical rollers are inserted between the followers and the cam. In the third method, specially shaped pads are inserted between the cam and the followers. Finite element analysis (FEA) using ANSYS Mechanical software is carried out to compare between these methods regarding the generated contact stresses between the cam and the followers. FEA is also utilized to design a self-integrated priming spring in the external lips of the followers in order to allow smooth pump start up at all operating conditions. The suction and delivery valves of this pump are crucial for its reliability and high performance. They should allow high flow rates at small pressure drop and should be compact, of low inertia to operate at high frequency, and of minimum deformation under high pressures. A CFD analysis for a proposed design for these valves is performed using ANSYS/FLUENT program on three-dimensional models, where the flow rates, the pressure and velocity distributions, and the deformations of these elements are calculated.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

scholarly journals Energetic and exergetic analysis of a convective drier: A case study of potato drying process

2020 ◽  
Vol 5 (1) ◽  
pp. 563-572
Author(s):  
Iman Golpour ◽  
Mohammad Kaveh ◽  
Reza Amiri Chayjan ◽  
Raquel P. F. Guiné
Keyword(s):  
Energy Consumption ◽  
Research Work ◽  
Specific Energy Consumption ◽  
Exergy Efficiency ◽  
Operating Conditions ◽  
Energy Utilization ◽  
Convective Drying ◽  
Drying Time ◽  
Energy And Exergy ◽  
Exergy Losses

AbstractThis research work focused on the evaluation of energy and exergy in the convective drying of potato slices. Experiments were conducted at four air temperatures (40, 50, 60 and 70°C) and three air velocities (0.5, 1.0 and 1.5 m/s) in a convective dryer, with circulating heated air. Freshly harvested potatoes with initial moisture content (MC) of 79.9% wet basis were used in this research. The influence of temperature and air velocity was investigated in terms of energy and exergy (energy utilization [EU], energy utilization ratio [EUR], exergy losses and exergy efficiency). The calculations for energy and exergy were based on the first and second laws of thermodynamics. Results indicated that EU, EUR and exergy losses decreased along drying time, while exergy efficiency increased. The specific energy consumption (SEC) varied from 1.94 × 105 to 3.14 × 105 kJ/kg. The exergy loss varied in the range of 0.006 to 0.036 kJ/s and the maximum exergy efficiency obtained was 85.85% at 70°C and 0.5 m/s, while minimum exergy efficiency was 57.07% at 40°C and 1.5 m/s. Moreover, the values of exergetic improvement potential (IP) rate changed between 0.0016 and 0.0046 kJ/s and the highest value occurred for drying at 70°C and 1.5 m/s, whereas the lowest value was for 70°C and 0.5 m/s. As a result, this knowledge will allow the optimization of convective dryers, when operating for the drying of this food product or others, as well as choosing the most appropriate operating conditions that cause the reduction of energy consumption, irreversibilities and losses in the industrial convective drying processes.

Investigation of the different particle size dust releases from rigid filter candles during pulse-jet cleaning

2021 ◽  
pp. 095440622110179
Author(s):  
Xin Luan ◽  
Zhongli Ji ◽  
Longfei Liu ◽  
Ruifeng Wang
Keyword(s):  
Particle Size ◽  
Critical Role ◽  
Operating Conditions ◽  
Solid Particles ◽  
Dust Particles ◽  
Cleaning Efficiency ◽  
Term Operation ◽  
Cleaning Performance ◽  
Experimental Apparatus ◽  
Pulse Jet

Rigid filters made of ceramic or metal are widely used to remove solid particles from hot gases at temperature above 260 °C in the petrochemical and coal industries. Pulse-jet cleaning of fine dust from rigid filter candles plays a critical role in the long-term operation of these filters. In this study, an experimental apparatus was fabricated to investigate the behavior of a 2050 mm filter candle, which included monitoring the variation of pressure dynamic characteristics over time and observing the release of dust layers that allowed an analysis of the cleaning performance of ISO 12103-1 test dusts with different particle size distributions. These results showed the release behavior of these dusts could be divided into five stages: radial expansion, axial crack, flaky release, irregular disruption and secondary deposition. The cleaning performance of smaller sized dust particles was less efficient as compared with larger sized dust particles under the same operating conditions primarily because large, flaky-shaped dust aggregates formed during the first three stages were easily broken into smaller, dispersed fragments during irregular disruption that forced more particles back to the filter surface during secondary deposition. Also, a “low-pressure and long-pulse width” cleaning method improved the cleaning efficiency of the A1 ultrafine test dust from 81.4% to 95.9%.

Using CFD to Enhance the Preliminary Design of High-Pressure Steam Turbines

2013 ◽  
Author(s):  
Juri Bellucci ◽  
Federica Sazzini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Design Tool ◽  
Tip Clearance ◽  
Large Set ◽  
Preliminary Design ◽  
Steam Turbines ◽  
High Pressure Steam ◽  
Wide Range ◽  
Pressure Steam

This paper focuses on the use of the CFD for improving a steam turbine preliminary design tool. Three-dimensional RANS analyses were carried out in order to independently investigate the effects of profile, secondary flow and tip clearance losses, on the efficiency of two high-pressure steam turbine stages. The parametric study included geometrical features such as stagger angle, aspect ratio and radius ratio, and was conducted for a wide range of flow coefficients to cover the whole operating envelope. The results are reported in terms of stage performance curves, enthalpy loss coefficients and span-wise distribution of the blade-to-blade exit angles. A detailed discussion of these results is provided in order to highlight the different aerodynamic behavior of the two geometries. Once the analysis was concluded, the tuning of a preliminary steam turbine design tool was carried out, based on a correlative approach. Due to the lack of a large set of experimental data, the information obtained from the post-processing of the CFD computations were applied to update the current correlations, in order to improve the accuracy of the efficiency evaluation for both stages. Finally, the predictions of the tuned preliminary design tool were compared with the results of the CFD computations, in terms of stage efficiency, in a broad range of flow coefficients and in different real machine layouts.

Research on the Structural Performance of Large-Tonnage Gantry Crane

2013 ◽  
Vol 823 ◽  
pp. 247-250
Author(s):  
Jie Dong ◽  
Wen Ming Cheng ◽  
Yang Zhi Ren ◽  
Yu Pu Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Calculations ◽  
Complex Structure ◽  
Early Period ◽  
Operating Conditions ◽  
Structural Performance ◽  
Gantry Crane ◽  
Element Analysis ◽  
Design And Manufacture

Because of the huge lifting weight and complex structure of large-tonnage gantry crane and in order to effectively design and review it, this paper aims to carry out a research on its structural performance based on the method of theoretical calculation and finite element analysis. During the early period of design, the method of theoretical calculations is adopted, and after specific design it comes the finite element analysis, so as to get the results of analysis under a variety of operating conditions, which illustrates that the structural design and review of large-tonnage gantry crane based on theoretical calculations and finite element are feasible, and also verifies that the method of finite element is an effective way to find a real dangerous cross-section, thus providing the basis for the design and manufacture of the crane structure.

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