scholarly journals Design Optimization of the Modified Planetary Carrier

2021 ◽  
Vol 8 (1) ◽  
pp. E17-E22
Author(s):  
S. Janigová ◽  
B. Schürger
Keyword(s):  
Fatigue Life ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Production Costs ◽  
Static Fatigue ◽  
New Model ◽  
Maximum Deformation ◽  
Planetary Gearbox ◽  
Single Piece ◽  
Third Stage

This paper aims to design a new model of the third-stage carrier assembly used in a planetary gearbox as a single part component with improved strength and fatigue life properties and lower production costs. First, the mounting carrier assembly is subjected to static, fatigue, and modal analysis, and based on obtained results, the operating conditions that ensure its trouble-free operation are proposed. In the next step, new designs of the carrier as a single piece component are proposed and subjected to similar analyses. The proper numerical analysis method is chosen to evaluate the fatigue life, total deformation, and von Misses stress for each new model. Based on these results, the best design is chosen and submitted to further improvement, ensuring a weight reduction of 5 %. This last model of the carrier assembly is the most optimal solution since the maximum deformation values decreased by more than 55 %, and the maximum von Misses stresses decreased by almost 38 %, which increased fatigue life. A more comprehensive range of operating conditions for the optimized carrier is proposed to ensure its suitability for use in each gearbox. The finite element method analysis is performed in ANSYS.

The Strength Analysis of Francis Turbine Runner Based on the Fluid-Solid Coupling

2014 ◽  
Vol 709 ◽  
pp. 41-45
Author(s):  
Kan Kan ◽  
Yuan Zheng ◽  
Xin Zhang ◽  
Bin Sun ◽  
Hui Wen Liu
Keyword(s):  
Water Pressure ◽  
Eastern China ◽  
Static Stress ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Strength Analysis ◽  
Maximum Deformation ◽  
The North ◽  
North Eastern ◽  
Turbine Runner

This paper does unidirectional fluid-solid coupling calculation on the runner strength under three designed head loading conditions of a certain Francis turbine in the north-eastern China. The water pressure on the blade in the flow fields of different operating conditions is calculated by means of CFD software CFX. With the help of ansys workbench, the water pressure is loaded to the blade as structural load to conclude the static stress distribution and deformation of the runner under different operating conditions. The results show that the maximum static stress increases with the rise of the flow and appears near the influent side of the blade connected to the runner crown; the maximum deformation increases with the rise of the flow and appears on the band. The results provides effective basis for the structural design and safe operation of the Francis turbine.

scholarly journals Integration of Operability Framework and Pareto Optimal Front to Calculate Optimal Condition of Ethane Cracking Process

2020 ◽  
pp. 105-113
Author(s):  
M. Farsi
Keyword(s):  
Pareto Front ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Operating Conditions ◽  
Base Case ◽  
Pareto Optimal ◽  
Multi Objective Optimization ◽  
Pareto Optimal Front ◽  
Multi Objective ◽  
Cracking Process

The main aim of this research is to present an optimization procedure based on the integration of operability framework and multi-objective optimization concepts to find the single optimal solution of processes. In this regard, the Desired Pareto Index is defined as the ratio of desired Pareto front to the Pareto optimal front as a quantitative criterion to analyze the performance of chemical processes. The Desired Pareto Front is defined as a part of the Pareto front that all outputs are improved compared to the conventional operating condition. To prove the efficiency of proposed optimization method, the operating conditions of ethane cracking process is optimized as a base case. The ethylene and methane production rates are selected as the objectives in the formulated multi-objective optimization problem. Based on the simulation results, applying the obtained operating conditions by the proposed optimization procedure on the ethane cracking process improve ethylene production by about 3% compared to the conventional condition.  

scholarly journals Determining the causes, prevention and elimination of unstable modes of gas turbochargers of marine diesels

2021 ◽  
Vol 27 (1) ◽  
pp. 33-51
Author(s):  
Володимир Миколайович Калугін ◽  
Олександр Міхайлович Мунтян
Keyword(s):  
Waste Heat ◽  
Operating Experience ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Heat Recovery Boiler ◽  
Effective Functioning ◽  
Contractual Arrangements ◽  
Safe Level ◽  
Air Supply ◽  
Trial Test

Annotation – With commissioning of the “Socofl Star” ship’s series, negative occurrences relative to surging of the Main Engine (ME) «Hanshin Diesel» 6LF46 turbochargers (TC) VTR 401-2. To elimination of a surging, it was necessary reduce loading of ME to the safe level. This action caused the ship’s speed to fall from 11 – 10 to 4 knots which resulted in worsening of the ship’s maneuverability characteristics and lead to the failure to provide the ship’s service speed stipulated in the contractual arrangements. Existence of this problem instigated the shipowner to charge us as experts with the mission of carrying out appropriate investigations and working out recommendations as to how to prevent and eliminate surging of TC. This task was solved on the m/v “Socofl Star”. Based on results the ME shop test and trial test of the vessel and also the saved-up data of work of ME in various conditions of swimming, the analysis of the causes of a surge of the TC was made. It is established that small values of safety factor of stability of the compressor of TC on a surging – KCT which are not allowing to ensure effective functioning of TC on the main modes of loading of ME are its reason. For increase in area of steady work of TC it is necessary to reduce the hydraulic resistance of components of the Air-Gas Path (AGP) of the ME which can be realized by changes in a design of units of air supply and gas exchange or reduction of productivity and extent of increase in pressure of air in the compressor of TC. Under operating conditions vessels an optimal solution an objective is removal of a part of blowing-off air after compressor of the TC. The air can be discharged into the flue gas header after the waste heat recovery boiler or directly into the atmosphere. This allowed the shipowner not to make constructive changes to the components of the AGP of ME and TC. The description of the operated unloading device controlled remotely on removal of air which ensures effective functioning of TC and ME that is confirmed by results of natural tests and the subsequent operating experience of vessels of the “Socofl Star” series is provided.

Evaluation of acoustic emission burst detection methods in a gearbox under different operating conditions

2018 ◽  
Vol 25 (4) ◽  
pp. 895-906 ◽  
Author(s):  
F. Leaman ◽  
C. Niedringhaus ◽  
S. Hinderer ◽  
K. Nienhaus
Keyword(s):  
Acoustic Emission ◽  
Processing Technique ◽  
Operating Conditions ◽  
Detection Methods ◽  
Threshold Values ◽  
Burst Detection ◽  
Signal Processing Technique ◽  
Planetary Gearbox ◽  
Machine Condition Monitoring ◽  
Definition Of

In account of its abilities to follow the damage progression, also at early stages, the acoustic emission (AE) analysis has become an attractive technique for machine condition monitoring. An AE analysis involves the detection of transients within the signals, which are called AE bursts. Traditional methods for AE burst detection are based on the definition of threshold values. When the machine under analysis works under variable operating conditions, threshold-based methods could lead to poor results due to the influence of these conditions on the AE generation. The present work compares the ability of three AE burst detection methods in a planetary gearbox working under different rotational speeds and loads. The results showed that performance could be significantly improved by using factors of the root mean square value as threshold values instead of fixed values. Among the evaluated methods, the method that includes demodulation and differentiation as a signal processing technique had the best performance overall.

Analytical determination of the optimal clearance for the fatigue life of ball bearing under different load conditions

2021 ◽  
pp. 1-28
Author(s):  
Bin Fang ◽  
Jinhua Zhang
Keyword(s):  
Fatigue Life ◽  
Load Distribution ◽  
Life Prediction ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Analytical Determination ◽  
Parameters Selection ◽  
Bearing Life ◽  
Structural Design Optimization ◽  
Load Conditions

Abstract In this paper, a comprehensive analytical model for the fatigue life prediction of ball bearing in various operating conditions is presented. Not only the internal clearance variations induced by the centrifugal expansion and assembly interference, but also ball inertia forces and ball-raceway separations are fully considered in theoretical modeling to achieve accurate life prediction of ball bearing. The model has been validated by comparison with the static results in previous literature. Based on this, the results of the load distribution and fatigue life versus the internal clearance of ball bearing under various operating conditions are studied. The results show that there is always an optimal clearance to maximize bearing fatigue life for the radial load or the combined load conditions, and the size of the optimal clearance for bearing life is determined by both the load conditions and rotating speeds to ensure the uniformity of the internal load distribution of the ball bearing. Therefore, the above theoretical and conclusions can be used in structural design optimization and assembly parameters selection of ball bearing to maximize the life characteristic.

Preliminary Design of Variable Nozzle Turbines Based on Sensitive Parameters

2020 ◽  
Author(s):  
Sebastian Wittwer ◽  
Ivo Sandor
Keyword(s):  
Engine Performance ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Experimental Results ◽  
Preliminary Design ◽  
Component Level ◽  
Gasoline Engines ◽  
Functional Parameters ◽  
Predictive Quality ◽  
Recent Developments

Abstract Recent developments in turbocharged gasoline engines have established new requirements for the turbine. A simple approach of scaling or optimizing existing turbines on component level might not be sufficient in terms of finding an optimal solution according to the multi-point, multi-disciplinary layout target. In the following paper nondimensional functional parameters are derived from turbomachinery analytics and rated on corresponding values of existing turbine stages. The influence of different parameters on aerodynamic performance is discussed based on CFD results and arranged according to their sensitivity for different engine relevant operating conditions. A metamodel for the preliminary design of variable nozzle turbine stages is derived from DoE (Design of Experiments) based CFD results. It is evaluated regarding its predictive quality on several exemplary turbine stages. Both, CFD and experimental results are therefore used while the experimental results are made up of hot gas stand measurements as well as measurements on engine test bench. Thus, not only the influence of functional parameters can be verified on turbine efficiency characteristics, but beyond that also the predictive quality of engine performance can be assessed.

scholarly journals Improvement of operation of steam cushion system for sensible thermal energy storage

2019 ◽  
Vol 116 ◽  
pp. 00107
Author(s):  
Ryszard Zwierzchowski
Keyword(s):  
Heat Flux ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Savings ◽  
Operating Conditions ◽  
Production Costs ◽  
Technical Solution ◽  
Atmospheric Air ◽  
Suction Pipe

The paper contains a method for improvement of operation of steam cushion system including its energy savings analyses, for a Thermal Energy Storage (TES) tank. Energy savings analyses were performed using operational data from selected Combined Heat and Power plants, which supply heat to large cities in Poland and are furnished with the TES. The role of the steam cushion system in the TES tank is to prevent the stored water against absorbing oxygen from atmospheric air. In the TES tank, which is a non-pressure tank, oxygen from atmospheric air could penetrate to the network water through the surge chamber and safety valves. The steam pressure under the roof is generated from technological steam injected under the roof. Energy savings in the steam cushion system are generated by using an appropriate technical solution for the upper orifice and suction pipe for circulation water, i.e., to make it movable through the use of pontoons. An isolating buffer layer is created at the top of the tank with very small convective and turbulent heat transport, which causes limited heat transfer from steam bed to the stored water in the tank. This results in heat flux of approximately 10% of the heat flux that occurs in the typical technical solution of the upper orifice and suction pipe for circulation water in the TES tank. This technology offers great opportunities to improve the operating conditions of District Heating System, cutting energy production costs and emissions of pollutants to the atmosphere.

Pattern recognition approach for acoustic emission burst detection in a gearbox under different operating conditions

2019 ◽  
Vol 25 (17) ◽  
pp. 2295-2304
Author(s):  
Félix Leaman ◽  
Cristián Molina Vicuña ◽  
Ralph Baltes ◽  
Elisabeth Clausen
Keyword(s):  
Pattern Recognition ◽  
Acoustic Emission ◽  
Condition Monitoring ◽  
Rotational Speed ◽  
Operating Conditions ◽  
Burst Detection ◽  
Threshold Method ◽  
Planetary Gearbox ◽  
Industrial Sectors ◽  
Artificial Neural Network Ann

Diverse machines in the mining, energy, and other industrial sectors are subject to variable operating conditions (OCs) such as rotational speed and load. Therefore, the condition monitoring techniques must be adapted to face this scenario. Within these techniques, the acoustic emission (AE) technology has been successfully used as a technique for condition monitoring of components such as gears and bearings. An AE analysis involves the detection of transients within the signals, which are called AE bursts. Traditional methods for AE burst detection are based on the definition of threshold values. When the machine under study works under variable rotational speed and load, threshold-based methods could produce inadequate results due to the influence of these OCs on the AE. This paper presents a novel burst detection method based on pattern recognition using an artificial neural network (ANN) for classification. The results of the method were compared to an adaptive threshold method. Experimental data were measured in a planetary gearbox test rig under different OCs. The results showed that both methods perform similarly when signals measured under constant OCs are considered. However, when signals are measured under different OCs, the ANN method performs better. Thus, the comparative analysis showed the good potential of the approach to improve an AE analysis of variable speed and/or load machines.

scholarly journals Should individuals migrate before acquiring education or after? A new model of Brain Waste vs. Brain Drain

2019 ◽  
Vol 19 (2) ◽  
Author(s):  
Elise S. Brezis
Keyword(s):  
Human Capital ◽  
Brain Drain ◽  
Return Migration ◽  
Optimal Solution ◽  
Unified Model ◽  
New Model ◽  
Unique Model ◽  
Migration Decisions ◽  
Timing Of Migration

AbstractShould individuals migrate before acquiring education or after? In order to analyze the optimality of the timing of migration, I develop a model of migration, which combines the two migration decisions into a unique model – the decisions about where to get an education and about where to work. The main reason for having a unified model is that investment in human capital cannot be disjoined from the decision about work. This paper shows that brain drain is usually an optimal solution. But, when we incorporate “brain waste” and “return migration”, then it is optimal to migrate when young.

Sign in / Sign up

Export Citation Format

Share Document