Mechanical Efficiency Optimization of a Sliding Vane Rotary Compressor

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Yuan Mao Huang ◽  
San Nan Tsay
Keyword(s):  
Genetic Algorithms ◽  
Major Axis ◽  
Mechanical Efficiency ◽  
Rotary Compressor ◽  
Friction Forces ◽  
Efficiency Optimization ◽  
Design Variables ◽  
Axis Length ◽  
Further Development ◽  
Polytropic Exponent

This study presents the mechanical efficiency optimization of a sliding vane rotary compressor by using genetic algorithms. Relevant air properties, volume segments, vane loadings and stresses, friction forces, compression power, and power loss are calculated to determine the mechanical efficiency of a compressor. Design variables include the major axis length and minor axis length of the elliptical stator inner contour, thickness, depth and width of vanes, mechanical efficiency, rotor rotational speed, polytropic exponent, and angular locations of the inlet and outlet ports. The effects of the mutation rate, crossover rate, and population size of the genetic algorithms on these design variables are studied. The vane is thin and the variation effects of vane dimensions on the mechanical efficiency of the compressor are less significant than other design variables. Therefore, the dimensions of vanes can be eliminated as design variables. The mechanical efficiency of the compressor is 0.55. The optimum values of these design variables are recommended for further development of the compressor.

The Load Acting on Bearings of Rotary Compressor Sliding Vanes

2003 ◽  
Author(s):  
Yuan Mao Huang ◽  
Chien Liang Li
Keyword(s):  
Air Pressure ◽  
Rotary Compressor ◽  
Experimental Setup ◽  
Radial Load ◽  
Compression Process ◽  
Measured Load ◽  
Polytropic Process ◽  
Study Designs ◽  
Further Development ◽  
Polytropic Exponent

This study designs extended rods with bearings for vanes and guider slots on covered plates to improve the performance of a sliding vane rotary compressor and determines the load acting on the bearings and vanes. A polytropic process with a polytropic exponent was assumed during the compression process to calculate the air pressure in the vane segments. The air pressure was used with Newton’s law to calculate loads acting on bearings and vanes. A compressor and experimental setup were also built to measure the radial load acting on the bearings. The measured load acting on the bearing was then compared with the calculated results. The exponent constant of 1.05 determined can be used for the further development of the compressor.

Design of a Rotary Vane Compressor by Genetic Algorithms

2001 ◽  
Author(s):  
Yuan Mao Huang ◽  
San Nan Tasy
Keyword(s):  
Major Axis ◽  
Ambient Air ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Genetic Optimization ◽  
Friction Forces ◽  
Volume Segment ◽  
Axis Length ◽  
Constrained Conditions ◽  
Rotary Vane Compressor

Abstract The genetic optimization algorithm method is used to design rotary compressors with sliding vanes. After the air properties, volume segment, compression power, loadings and stresses of vanes, friction forces and power loss are calculated, the objective function of the maximum efficiency and the constrained conditions can be derived and integrated. Using the ambient air conditions and the properties of Vespel, the effects of the mutation rate, crossover rate and population size of the genetic algorithm on the design parameters are studied. These design parameters include the major axis length, minor axis length, angular locations of inlet and outlet ports and rotational speed of the compressor, the thickness, depth and height of vanes, and the polytropic exponent. The efficiency of the compressor increases to 0.55 compared with the value of 0.4 obtained from the existing data.

scholarly journals Colorectal endoscopic submucosal dissection using the pocket-creation method with single clip traction: a feasibility study

2021 ◽  
Vol 09 (05) ◽  
pp. E653-E658
Author(s):  
Tatsuma Nomura ◽  
Yoshikazu Hayashi ◽  
Takaaki Morikawa ◽  
Masahiro Okada ◽  
Hisashi Fukuda ◽  
...  
Keyword(s):  
Endoscopic Submucosal Dissection ◽  
Major Axis ◽  
En Bloc Resection ◽  
Bloc Resection ◽  
Success Rates ◽  
En Bloc ◽  
Submucosal Dissection ◽  
Mucosal Incision ◽  
Axis Length ◽  
Colorectal Endoscopic Submucosal Dissection

Abstract Background and study aims The pocket-creation method (PCM) facilitates dissection of the central part of a tumor. We previously developed the PCM with clip traction (PCM-CT) to facilitate opening the mucosal pocket, which otherwise could become cumbersome. In the present study, we aimed to examine the feasibility of PCM-CT for colorectal endoscopic submucosal dissection (ESD). Patients and methods PCM-CT was performed on 30 patients with early colorectal tumors from October 2019 to April 2020. PCM-CT allows efficient opening of the mucosal pocket by using the PCM to dissect the center of the lesion and then apply traction with a single clip after making a circumferential mucosal incision. Results The median specimen major axis length, ESD time, ESD speed, and en bloc resection rate were 48 mm, 84 minutes, 20 mm2/min, and 100 % (30/30), respectively. The success rates for the traction clip and median single-clip-traction time were 100 % (30/30) and 1.5 minutes, respectively. Conclusions Colorectal ESD using PCM-CT is a simple and promising method.

Mathematical Modeling and Scaling of the Friction Losses of a Mechanical Gyroscope

2018 ◽  
Vol 10 (03) ◽  
pp. 1850024 ◽  
Author(s):  
Nicola Pozzi ◽  
Mauro Bonfanti ◽  
Giuliana Mattiazzo
Keyword(s):  
Wave Energy ◽  
Fluid Dynamic ◽  
Scaling Law ◽  
Full Scale ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Friction Forces ◽  
Efficiency Optimization ◽  
Energy Field ◽  
Model Of Friction

Friction is a complicated phenomenon that plays a central role in a wide variety of physical systems. An accurate modeling of the friction forces is required in the model-based design approach, especially when the efficiency optimization and system controllability are the core of the design. In this work, a gyroscopic unit is considered as case study: the flywheel rotation is affected by different friction sources that needs to be compensated by the flywheel motor. An accurate modeling of the dissipations can be useful for the system efficiency optimization. According to the inertial sea wave energy converter (ISWEC) gyroscope layout, friction forces are modeled and their dependency with respect to the various physical quantities involved is examined. The mathematical model of friction forces is validated against the experimental data acquired during the laboratory testing of the ISWEC gyroscope. Moreover, in the wave energy field, it is common to work with scale prototypes during the full-scale device development. For this reason, the scale effect on dissipations has been correlated based on the Froude scaling law, which is commonly used for wave energy converter scaling. Moreover, a mixed Froude–Reynolds scaling law is taken into account, in order to maintain the scale of the fluid-dynamic losses due to flywheel rotation. The analytical study is accompanied by a series of simulations based on the properties of the ISWEC full-scale gyroscope.

scholarly journals REDUCTION OF VIBRATIONS IN ELECTROMECHANICAL DRIVE SYSTEMS WITH VECTOR CONTROL

Transport ◽  
2004 ◽  
Vol 19 (6) ◽  
pp. 276-279
Author(s):  
Paweł Bachorz ◽  
Eugeniusz Switoński ◽  
Arkadiusz Meżyk
Keyword(s):  
Genetic Algorithms ◽  
Control System ◽  
Vector Control ◽  
Structural Parameters ◽  
Power Drive ◽  
Design Variables ◽  
Electromechanical Drive ◽  
Pi Controllers ◽  
Drive Systems ◽  
Vector Control System

This paper presents the issues of modelling electromechanical drive systems in a mechatronic approach. The effect of a vector control system on the dynamics of the system is shown. The optimisation of the system in order to minimise vibration amplitudes and amplitudes of forces in selected kinematic pairs of a high power drive system was performed with the use of genetic algorithms. Design variables of the optimisation process comprised the structural parameters of the mechanical part as well as the settings of PI controllers of the vector control system. The selected results of numerical computations are presented.

scholarly journals Numerical Investigation on the Sieving Performance of Elliptical Vibrating Screen

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1151
Author(s):  
Zhiquan Chen ◽  
Xin Tong ◽  
Zhanfu Li
Keyword(s):  
Major Axis ◽  
The Finite Element Method ◽  
Semi Major Axis ◽  
Vibration Direction ◽  
Maximum Deformation ◽  
Vibrating Screen ◽  
Performance Indexes ◽  
Screening Efficiency ◽  
Axis Length ◽  
Element Method

Screening techniques have been widely deployed in industrial production for the size-separation of granular materials such as coal. The elliptical vibrating screen has been regarded as an excellent screening apparatus in terms of its high screening efficiency and large processing capacity. However, its fundamental mechanisms and operational principles remain poorly understood. In this paper, the sieving process of an elliptical vibrating screen was numerically simulated based on the discrete element method (DEM), and an approach coupling the DEM and the finite element method (DEM–FEM) was introduced to further explore the collision impact of materials on the screen deck. The screening time, screening efficiency, maximum stress and maximum deformation were examined for the evaluation of sieving performance. The effects of six parameters—length of the semi-major axis, length ratio between two semi-axes, vibration frequency, inclination angle, vibration direction angle and vibration direction—on different sieving results were systematically investigated in univariate and multivariate experiments. Additionally, the relationships among the four performance indexes were discussed and the relational functions were obtained. The conclusions and methodologies presented in this work could be of great significance for the design and improvement of elliptical vibrating screens.

Mechanical Efficiency of Hydraulic Air Compressors

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Valeria Pavese ◽  
Dean Millar ◽  
Vittorio Verda
Keyword(s):  
Bubbly Flow ◽  
Mechanical Efficiency ◽  
Open Loop ◽  
Economic Implication ◽  
Intimate Contact ◽  
Air Compressor ◽  
Design Variables ◽  
Gas Compression ◽  
Large Heat ◽  
Air Compressors

After air and water mixing, the process of gas compression in the downcomer shaft or pipe of a hydraulic air compressor is considered nearly isothermal due to (i) the mass flow rate of water being typically of three orders higher than that of the gas it compresses, (ii) water having a heat capacity approximately four times that of air, and (iii) the intimate contact and large heat transfer area between the gas phase and the liquid phase of the bubbly flow. A formulation for estimation of the efficiency of a closed- or open-loop hydraulic air compressor, expressed in terms of the principal hydraulic air compressor design variables, is presented. The influence of a hitherto underappreciated factor affecting the performance of these installations, such as the solubility of the gas being compressed in the water, is explored. A procedure for estimating the yield of compressed gas, accounting for these solubility losses, is explained and used to determine the mechanical efficiency of historical hydraulic air compressor installations from reported performance data. The result is a significant downward revision of hydraulic air compressor efficiency by approximately 20% points in comparison to most reported efficiencies. However, through manipulation of cosolute concentrations in the water, and the temperature of the water (through regulation of the ejection of compression heat), the mechanical efficiency can be increased to the formerly reported levels. The thermo-economic implication of these efficiency determinations is that in a modern context, hydraulic air compressors may be able to outperform conventional mechanical gas compression equipment.

Optimum Design of the Continuously Variable Transmission for a Motorcycle

2001 ◽  
Author(s):  
Yuan Mao Huang ◽  
Bi Shyang Hu
Keyword(s):  
Simulated Annealing Algorithm ◽  
Continuous Variable ◽  
Design Parameters ◽  
Objective Functions ◽  
Design Variables ◽  
Continuous Variable Transmission ◽  
Product Method ◽  
Variable Transmission ◽  
Annealing Algorithm ◽  
Further Development

Abstract Many design parameters affect the performance of continuous variable transmissions. This paper presents the optimization of a continuous variable transmission by using the simulated annealing algorithm. The Bessel method of curve fitting and the tensor product method of surface fitting were used to facilitate the discrete fuel consumption, emissions of carbon monoxide (CO) and HC compound of experimental engine data. A compromise method was used to analyze the multi-objective functions. The values for design variables are recommended for further development.

scholarly journals The Central Bar in M 94

1996 ◽  
Vol 171 ◽  
pp. 422-422
Author(s):  
C. Möllenhoff ◽  
M. Matthias ◽  
O.E. Gerhard
Keyword(s):  
Major Axis ◽  
Stellar Kinematics ◽  
Semi Major Axis ◽  
Ionized Gas ◽  
Model Calculations ◽  
Gas Kinematics ◽  
Closed Orbits ◽  
Total Light ◽  
Axis Length ◽  
Global And Local

Surface photometry in I, J, K of the oval disk galaxy M 94 (NGC 4736) reveal a weak central stellar bar of 0.7 kpc semi-major axis length, comprising ≈ 14% of the total light within 20″. By stellar kinematics the existence of a small spheroidal bulge with v/à ≈ 0.8 was discovered. The ionized gas (Hα) in this region shows global and local deviations from the stellar kinematics. Model calculations of closed orbits for the cold gas in the combined potential of bar, disk, and bulge predict large non-circular motions in equilibrium flow. However, these do not fit the observed gas kinematics; obviously hydrodynamical forces play a role in the central region of M 94.

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