Simulation Research of a Type of Pressure Vessel under Complex Loading Part 2 Complex Load of the Numerical Analysis

2013 ◽  
Vol 756-759 ◽  
pp. 4662-4667
Author(s):  
Jun Chen Li ◽  
Jie Sheng ◽  
Zhang Yu Fu
Keyword(s):  
Pressure Vessel ◽  
Large Scale ◽  
Mechanical Response ◽  
Simulation Analysis ◽  
Complex Loading ◽  
Operating Conditions ◽  
Small Scale ◽  
Simulation Research ◽  
Complex Load ◽  
Calculation Results

Loading of pressure vessel was usually complicated in practical service operating conditions. Simulation model of pressure vessel was built by method of finite element simulation analysis, and structured mesh generation was realized. Numerical calculation was come true, stress/strain distribution of pressure vessel was obtained in applying of the multi-load. On this basis, this condition compared with alone applied many loadings. The calculation results indicate the validity of this model, and results are evaluated according to relevant standards, which provide a way to study mechanical response in the actual working conditions. In addition, sub-model is analyzed for key part of pressure vessel, and transition is come true from large scale simulation to small scale simulation.

Simulation Research of a Type of Pressure Vessel under Complex Loading Part 1 Component Load of the Numerical Analysis

2013 ◽  
Vol 756-759 ◽  
pp. 4656-4661
Author(s):  
Yu Fu Zhang ◽  
Hui Xia Guo ◽  
Jun Chen Li ◽  
Gui Rong Yang ◽  
Ying Ma ◽  
...  
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Geometric Modeling ◽  
Mechanical Response ◽  
Complex Loading ◽  
Strain Response ◽  
The Finite Element Method ◽  
Key Factors ◽  
Dead Weight ◽  
Simulation Research

Macroscopic mechanical response is one of the key factors in designing pressure vessel. A geometric modeling of pressure vessel was established and the mesh of this modeling then generated by using the finite element simulating methods in software ABAQUS. Loading and boundary conditions of dead weight, hydraulic and uniform internal pressure which often suffered pressure vessel were set and calculated by the finite element method. Stress/strain response of pressure vessel in all kinds of alone loading ways were obtained. The results of finite element simulating were in accordance with those of theoretical calculation which provided useful data for research on mechanical response of pressure vessel under complex loading conditions.

Wavelet Analysis on Eddy Structure in Micro Bubble Two Phase Flow Using PIV

2004 ◽  
Author(s):  
Ling Zhen ◽  
Claudia del Carmen Gutierrez-Torres
Keyword(s):  
Boundary Layer ◽  
Turbulent Flow ◽  
Drag Reduction ◽  
Large Scale ◽  
Operating Conditions ◽  
Small Scale ◽  
Turbulent Structures ◽  
Two Phase ◽  
Multi Scale ◽  
Eddy Structures

The question of “where and how the turbulent drag arises” is one of the most fundamental problems unsolved in fluid mechanics. However, the physical mechanism responsible for the friction drag reduction is still not well understood. Over decades, it is found that the turbulence production and self-containment in a boundary layer are organized phenomena and not random processes as the turbulence looks like. The further study in the boundary layer should be able to help us know more about the mechanisms of drag reduction. The wavelet-based vector multi-resolution technique was proposed and applied to the two dimensional PIV velocities for identifying the multi-scale turbulent structures. The intermediate and small scale vortices embedded within the large-scale vortices were separated and visualized. By analyzing the fluctuating velocities at different scales, coherent eddy structures were obtained and this help us obtain the important information on the multi-scale flow structures in the turbulent flow. By comparing the eddy structures in different operating conditions, the mechanism to explain the drag reduction caused by micro bubbles in turbulent flow was proposed.

The Finite Element Analysis of South Cap Excavation of Left Branching of Ma on Shan Yangtze River Highway Bridge

2011 ◽  
Vol 255-260 ◽  
pp. 4207-4211
Author(s):  
Yue Zhang ◽  
Mi Zhou
Keyword(s):  
Yangtze River ◽  
Simulation Analysis ◽  
Soft Soil ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Highway Bridge ◽  
Foundation Pit ◽  
Element Analysis ◽  
Calculation Results ◽  
Stress And Deformation

South pile foundation of Ma On Shan Yangtze River Highway Bridge is big, deep, soft soil, groundwater rich. In order to guarantee the safeties of the foundation, its foundation pit supporting schemes are compared, selected and calculated, finally lock mouth steel pipe support is selected as the design and construction scheme. The three-dimensional simulation analysis of the scheme is calculated by using MIDAS software, simulated four construction condition is presented, and stress and deformation results of retaining structure on various operating conditions is obtained. The calculation results show that the palisade structure basic satisfies the requirements of caps excavation and caps concrete construction. The results of construction show that the construction method, model and parameters used in this paper are basic right, the reasonableness of Supporting is confirmed and for the similar large foundation pit construction provides useful reference.

scholarly journals Experimental Investigation of a Small-Scale ORC Power Plant Using a Positive Displacement Expander with and without a Regenerator

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1452 ◽  
Author(s):  
Collings ◽  
Mckeown ◽  
Wang ◽  
Yu
Keyword(s):  
Heat Exchanger ◽  
Power Plants ◽  
Large Scale ◽  
Internal Heat ◽  
Expansion Ratio ◽  
Operating Conditions ◽  
Working Fluid ◽  
Small Scale ◽  
Regenerative Heat ◽  
Positive Displacement

While large-scale ORC power plants are a relatively mature technology, their application to small-scale power plants (i.e., below 10 kW) still encounters some technical challenges. Positive displacement expanders are mostly used for such small-scale applications. However, their built-in expansion ratios are often smaller than the expansion ratio required for the maximum utilisation of heat sources, leading to under expansion and consequently higher enthalpy at the outlet of the expander, and ultimately resulting in a lower thermal efficiency. In order to overcome this issue, one possible solution is to introduce an internal heat exchanger (i.e., the so-called regenerator) to recover the enthalpy exiting the expander and use it to pre-heat the liquid working fluid before it enters the evaporator. In this paper, a small-scale experimental rig (with 1-kW rated power) was designed and built that is capable of switching between regenerative and non-regenerative modes, using R245fa as the working fluid. It has been tested under various operating conditions, and the results reveal that the regenerative heat exchanger can recover a considerable amount of heat when under expansion occurs, increasing the cycle efficiency.

Review of Expander Selection for Small-Scale Organic Rankine Cycle

2014 ◽  
Author(s):  
Saeedeh Saghlatoun ◽  
Weilin Zhuge ◽  
Yangjun Zhang
Keyword(s):  
Internal Combustion Engines ◽  
Large Scale ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Small Scale ◽  
Manufacturing Cost ◽  
Operating Characteristics ◽  
Small Scale Industries

After more than twenty years working on the selection of an appropriate expander for Organic Rankine cycles and wide research and attentions about its influence on the performance and total cost of waste heat recovery systems, now there is a good-enough background studies and achievement for large scale applications. But small-scale industries is like a art space to modify and revise the previous results. As it is clearly known, in small-scale applications and industries especially in internal combustion engines, besides the investigation of performance, physical properties and final efficiency of expander, other parameters should be analyzed accurately like manufacturing cost, availability, reliability, sensitivity to operating condition fluctuations. Due to a significant role of expander equipment to enhance the efficiency of ORC system in the first step expanders is investigated. In this paper, as per related operating characteristics, a complete comparison of small-scale expanders will be debated to guide designers to select more appropriate and the best efficient expansion machine as per their requirements. According to available literatures there is more need to do research about different types of expanders with various operating conditions in small-scale industries.

Dispersive Mixing Consideration of Twin-Screw Compounding Scale-Up Methodologies

2015 ◽  
Author(s):  
Benjamin Dryer ◽  
Graeme Fukuda ◽  
Jake Webb ◽  
David I. Bigio ◽  
Mark Wetzel ◽  
...  
Keyword(s):  
Material Properties ◽  
Large Scale ◽  
Scale Up ◽  
Polymer Melt ◽  
Operating Conditions ◽  
Small Scale ◽  
Twin Screw ◽  
Industry Practice ◽  
Break Up ◽  
Dispersive Mixing

Twin-screw polymer extrusion has shown increased utility for creating composite materials. However, in order to achieve the desired product properties, sufficient mixing is essential. Dispersive mixing, or the breaking-up of particle agglomerates, is critical to create filled compounds with the required material properties. In a twin-screw compounding process, the Residence Stress Distribution (RSD) has been used to quantify the dispersive mixing induced by the stresses in the polymer melt. These stresses are quantified by the percent break-up of stress-sensitive polymeric beads. It was found that the amount of material that experiences the critical stress is a function of the operating conditions of screw speed and specific throughput [1]. The quantification of dispersive mixing allows for better control of a compounding process and can be used to design new processes. During the development of a new compounding process, screw geometries and operating conditions are often refined on a laboratory-scale extruder and then scaled up to a manufacturing level. Scale-up rules are used to translate the operating conditions of a process to different sizes of extruders. In a compounding process, the goal when scaling-up is to maintain the same material properties on both scales by achieving equivalent mixing. The RSD methodology can be used to evaluate the effectiveness of scale-up rules by comparison between two or more scales. This paper will demonstrate the utility of the RSD in evaluation of two unique scale-up rules. Conventional industry practice is based on the volumetric flow comparison between extruders. The proposed approach demonstrates that in order to maintain equivalent dispersive mixing between different sizes of extruders, the degree of fill, or the percent drag flow (%DF), must be kept equivalent in the primary mixing region. The effectiveness of both rules has been evaluated by experimental application of the RSD methodology. A design of experiment approach was used to generate predictive equations for each scale-up rule that were compared to the behavior of the original small-scale extruder. Statistical comparison of the two scale-up rules showed that the %DF rule predicted operating conditions on the large-scale extruder that produced percent break-up behavior more similar to the small-scale behavior. From these results, it can be concluded that the %DF scale-up rule can be used to accurately scale operating conditions between different-sized extruders to ensure similar dispersive mixing between two processes. This will allow for greater accuracy when recreating the material properties of a small-scale twin-screw compounding process on a larger, mass production machine.

scholarly journals Study on Multi-Scale Coupled Ecological Dispatching Model Based on the Decomposition-Coordination Principle

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1443
Author(s):  
Zhou ◽  
Dong ◽  
Wang ◽  
Shi ◽  
Gao ◽  
...  
Keyword(s):  
Large Scale ◽  
Scale Model ◽  
Small Scale ◽  
Adaptive Genetic Algorithm ◽  
Hydrologic Alteration ◽  
Multi Scale ◽  
Large Scale Model ◽  
Calculation Results ◽  
Coordination Principle ◽  
Small Scale Model

Studies on environmental flow have developed into a flow management strategy that includes flow magnitude, duration, frequency, and timing from a flat line minimum flow requirement. Furthermore, it has been suggested that the degree of hydrologic alteration be employed as an evaluation method of river ecological health. However, few studies have used it as an objective function of the deterministic reservoir optimal dispatching model. In this work, a multi-scale coupled ecological dispatching model was built, based on the decomposition-coordination principle, and considers multi-scale features of ecological water demand. It is composed of both small-scale model and large-scale model components. The small-scale model uses a daily scale and is formulated to minimize the degree of hydrologic alteration. The large-scale model uses a monthly scale and is formulated to minimize the uneven distribution of water resources. In order to avoid dimensionality, the decomposition coordination algorithm is utilized for the coordination among subsystems; and the adaptive genetic algorithm (AGA) is utilized for the solution of subsystems. The entire model—which is in effect a large, complex system—was divided into several subsystems by time and space. The subsystems, which include large-scale and small-scale subsystems, were correlated by coordinating variables. The lower reaches of the Yellow River were selected as the study area. The calculation results show that the degree of hydrologic alteration of small-scale ecological flow regimes and the daily stream flow can be obtained by the model. Furthermore, the model demonstrates the impact of considering the degree of hydrologic alteration on the reliability of water supply. Thus, we conclude that the operation rules extracted from the calculation results of the model contain more serviceable information than that provided by other models thus far. However, model optimization results were compared with results from the POF approach and current scheduling. The comparison shows that further reduction in hydrologic alteration is possible and there are still inherent limitations within the model that need to be resolved.

Mixed Elastohydrodynamic Lubrication in a Partial Journal Bearing—Comparison Between Deterministic and Stochastic Models

2006 ◽  
Vol 128 (4) ◽  
pp. 778-788 ◽  
Author(s):  
Mihai B. Dobrica ◽  
Michel Fillon ◽  
Patrick Maspeyrot
Keyword(s):  
Large Scale ◽  
Deterministic Model ◽  
Elastohydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Mixed Lubrication ◽  
Operating Conditions ◽  
Small Scale ◽  
Depth Analysis ◽  
Stochastic Solution ◽  
Mixed Lubrication Regime

The analysis of the mixed lubrication phenomena in journal and axial bearings represents nowadays the next step towards a better understanding of these devices, subjected to more and more severe operating conditions. While the theoretical bases required for an in-depth analysis of the mixed-lubrication regime have long been established, only small-scale numerical modeling was possible due to computing power limitations. This led to the appearance of averaging models, thus making it possible to generalize the trends observed in very small contacts, and to include them in large-scale numerical analyses. Unfortunately, a lack of experimental or numerical validations of these averaging models is observed, so that their reliability remains to be demonstrated. This paper proposes a deterministic numerical solution for the hydrodynamic component of the mixed-lubrication problem. The model is applicable to small partial journal bearings, having a few centimeters in width and diameter. Reynolds’ equation is solved on a very thin mesh, and pad deformation due to hydrodynamic pressure is taken into account. Deformation due to contact pressure is neglected, which limits the applicability of the model in those cases where extended contact is present. The results obtained with this deterministic model are compared to the stochastic solution proposed by Patir and Cheng, in both hydrodynamic and elastohydrodynamic regimes. The rough surfaces used in this study are numerically generated (Gaussian) and are either isotropic or oriented, having different correlation lengths. It is shown that the stochastic model of Patir and Cheng correctly anticipates the influence of roughness over the pressure field, for different types of roughness. However, when compared to the smooth surface solution, the correction introduced by this model only partially compensates for the differences observed with a deterministic analysis.

Simulation Analysis on Harmonics Pollution of Large-Scale Wind System Accessed to Grid

2014 ◽  
Vol 997 ◽  
pp. 795-799
Author(s):  
Chen Liang ◽  
Mei Yang ◽  
Wei Zheng ◽  
Yong Zhi
Keyword(s):  
Power System ◽  
Wind Power ◽  
Power Flow ◽  
Large Scale ◽  
Simulation Analysis ◽  
Wind System ◽  
Harmonic Pollution ◽  
Calculation Results ◽  
Power Grid Planning ◽  
Grid Planning

The harmonic sources model of wind grid accessed to power system is established by measurement and statistical methods based on the large scale wind system planning of Gansu jiuquan area. The harmonic power flow is analysed under different operation modes in power system. The harmonic pollution trend of the million kilowatt wind accessed to power system at present stage and 2015 are analysed and compared, the calculation results show that the harmonics pollution is most serious at the point which wind power accessed to the network, the harmonic pollution degree is damping along the line. The farther electrical distance from harmonic sources, the fewer harmonic, and the harmonic pollution is decreasing with the grid structure constantly reinforced. This research will provide reference data for power grid planning and wind power quality management.

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