Validation of a numerical model to support the design of additively manufactured aerostatic dry gas seals carried out on a test bench through use of seals with defined permeabilities

2021 ◽  
Author(s):  
Schaham Schoar ◽  
Arno Elspaß ◽  
Stefan Kleszczynski ◽  
Hans Josef Dohmen ◽  
Friedrich-Karl Benra
Keyword(s):  
Numerical Model ◽  
Test Bench ◽  
Gas Seals

scholarly journals Numerical Investigation of a Wood-Chip Downdraft Gasifier

2019 ◽  
Vol 113 ◽  
pp. 01002
Author(s):  
Alessandro Vulpio ◽  
Nicola Casari ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Alessio Suman
Keyword(s):  
Numerical Model ◽  
Test Bench ◽  
Wood Chip ◽  
Biomass Gasification ◽  
Careful Analysis ◽  
Good Match ◽  
Energy Field ◽  
Downdraft Gasifier ◽  
Virtual Test ◽  
Working Parameters

Biomass gasification is regarded as one of the most promising technology in the renewable energy field. The outcome of such operation, i.e. the synfuel, can be exploited in several ways, for example powering engines and turbines, and is considered more flexible than the biomass itself. For this reason, a careful analysis of the gasification performance is of paramount importance for the optimization of the process. One of the techniques that can be used for such a purpose, is the numerical analysis. CFD is indeed a tool that can be of great help in the design and study of the operation of the gasifier, allowing for an accurate prediction of the operating parameters. In this work, a downdraft gasifier is considered, and the biomass is made of wood chip. The present analysis is devoted to build the numerical model and simulate all the reactions that happen inside an actual gasifier, considering the drying of the wood chip, heating, pyrolysis, and combustion. Good match with experimental results is found, making the numerical model here presented a reliable virtual test bench where investigating the effects of variation in the working parameters.

Numerical Analysis of General Groove Geometry for Dry Gas Seals

2013 ◽  
Vol 457-458 ◽  
pp. 544-551
Author(s):  
Ji Bin Hu ◽  
Wen Jin Tao ◽  
Yi Min Zhao ◽  
Chao Wei
Keyword(s):  
Numerical Model ◽  
Hydrodynamic Pressure ◽  
Computational Domain ◽  
System Transformation ◽  
Modeling And Analysis ◽  
Gas Seals ◽  
Groove Seal ◽  
Shallow Groove ◽  
Regular Region ◽  
Volume Method

By Changing the key points on the spiral curve, general groove geometry was determined. Considering the simplicity of modeling and analysis, cubic spline function was used to express the general groove profile. By using the boundary fitted coordinate system transformation, irregular computational domain was transferred to regular region; Based on flow conservation principle, finite volume method was applied to discrete compressible Reynolds equation; By the application of Newton-Raphson iteration method for solving algebraic equation, numerical model of general groove dry gas seals was established. When compared sample results with shallow groove theory, the capacity and stiffness of numerical results match well with theoretical ones, verifying the accuracy of novel numerical model. Through analysis of three typical groove seals, spiral groove seal has strongest carrying capacity. Pressure distribution of three groove seals subjects to the law of hydrodynamic pressure effect. And the numerical model established in this paper will offer a general calculate platform for optimization of groove geometry in the future.

scholarly journals Improvement of Properties of an Insulated Wall for Refrigerated Trailer-Numerical and Experimental Study

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 51
Author(s):  
Konrad Zdun ◽  
Tadeusz Uhl
Keyword(s):  
Numerical Model ◽  
Phase Change ◽  
Phase Change Material ◽  
Test Bench ◽  
Cooling System ◽  
Experimental Tests ◽  
Primary Energy ◽  
Wall Structure ◽  
Cold Store ◽  
Change Material

In the paper, we report our research on the improvement of thermal efficiency of refrigerated trailers by modification of their wall structure by placing a layer of phase change material inside them. The research was carried out in the field of transport, meeting the requirements of all classes provided for in the ATP agreement for refrigerated trailers. As part of the research, we formulated a numerical model of the proposed design of the refrigerator walls, which was subsequently validated by comparing the modeling results with the results of experimental tests carried out on a test bench designed specifically for this purpose. Based on the validated simulation conditions, we formulated the numerical model of a full-scale refrigerated semi-trailer, which was numerically tested under the conditions specified in the ATP Agreement. The results proved that adding a 6 mm layer of the SP-24 phase change material in each of the walls of the cold store allows the temperature inside the trailer to be kept below −20 °C for a period of 24 h without the need to supply cold from the outside during operation. The passive refrigerated semi-trailer system implemented in this manner with 6 mm PCM layer allows for a reduction in primary energy consumption by up to 86% in a period of 22 h. The mentioned percentage did not take into account the efficiency of the cooling system of the phase change material.

Comparison of Simulations and Experiments of Loaded Spiral Bevel Gears Behavior

2015 ◽  
Author(s):  
Joël Teixeira Alves ◽  
J. P. de Vaujany ◽  
M. Guingand
Keyword(s):  
Numerical Model ◽  
Computer Aided Design ◽  
Test Bench ◽  
Logarithmic Spiral ◽  
Transmission Error ◽  
Milling Machine ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Computer Aided ◽  
Spiral Bevel

The design of spiral bevel gears is still very complex because tooth geometry and thus kinematics performance depend on the manufacturing process of this type of gear. The cutting process is dominated by two major manufacturers: Gleason and Klingelnberg. The shape of the teeth surfaces are governed by a large number of programmed machine settings, so they cannot be optimized intuitively. Due to the progress made during the last decade by CNC machines and CAM (Computer Aided Manufacturing) softwares, it is now possible to manufacture spiral bevel gears with quite good quality on a 5-axis milling machine. In a previous study, the authors presented a numerical model for calculating the quasi-static load sharing of spiral bevel gears. Two kinds of geometries were developed: a simplified Gleason type, and a geometry based on classical spherical involutes combined with a logarithmic spiral. After being generated using a CAD (Computer-Aided Design) software, these two geometries were manufactured with a 5-axis milling machine controlled by CAM software. A metrological study showed that manufacturing by a 5-axis milling machine can be an alternative to conventional cutting methods. The aim of the present paper is to validate the numerical model. To reach this goal, a test bench was designed to measure the loaded transmission error and visualize the contact patterns. The test bench is integrated inside a numerical 3-axis milling machine: the pinion is mounted on the spindle, while the base of the bench is clamped on its plate. Thus assembly errors can be imposed easily and accurately. Measured and simulated transmission errors are then compared for different axis misalignments cases.

Experimental Validation of the Modified Continuously Variable Command Law of a Semi-Active Suspension Integrating a Magneto-Rheological (MR) Damper

2014 ◽  
Vol 1016 ◽  
pp. 279-286
Author(s):  
Said Boukerroum ◽  
Nacer Hamzaoui
Keyword(s):  
Numerical Model ◽  
Degrees Of Freedom ◽  
Test Bench ◽  
Mr Damper ◽  
Active Suspension ◽  
Suspension System ◽  
Compression And Expansion ◽  
Low Speeds ◽  
Secondary Suspension ◽  
Magneto Rheological

The present work consists of an experimental performances analysis of a suspension system with two degrees of freedom governed by a semi-active modified continuously variable command (MCVC) law. The internal dynamics of Magneto-Rheological (MR) damper used in this study is highlighted by the modified Bouc-Wen model in the mathematical modelling of the secondary suspension system. After the dynamic characterization of the MR damper, a comparison of performance obtained by this control scheme is carried out from the responses calculated using a numerical model and measured experimentally from a test bench of a semi-active suspension incorporating an MR damper and controlled by a dSPACE control chain. For a better representativeness of the modified Bouc-Wen numerical model, a rapprochement between the calculated and measured responses for the same dynamic characteristics of the test bench is possible by adjusting the most influential parameters of the numerical model. Through better management of the suspension during the low speeds, the modified Bouc-Wen model is more representative of the real behaviour of the MR damper, given its sensitivity at these low speeds during transitions between compression and expansion phases of the damper.

Torsion Vibrations and Dynamic Stability of a Marine Driveline With Hydraulically Actuated Multi-Disk Clutch

2018 ◽  
Author(s):  
Mauro Cavallin ◽  
Alberto Doria ◽  
Giovanni Meneghetti ◽  
Daniele Sacchi
Keyword(s):  
Numerical Model ◽  
Test Bench ◽  
Experimental Tests ◽  
Friction Model ◽  
Lugre Model ◽  
Parametric Stability ◽  
Specific Test ◽  
Lugre Friction Model ◽  
Lugre Friction ◽  
The Stability

The driveline of many crafts during mooring maneuvers operates in the “trolling” mode, which is characterized by large slippages of the clutch. Sometimes the properties of clutch material and oil lead to the onset of self-excited torsion vibrations and wide fluctuations in torque. To analyze this phenomenon a numerical model of a typical marine driveline is developed, friction characteristics of the clutch are simulated by means of a LuGre model. A parametric stability analysis is carried out to highlight the effect of the parameters of the LuGre friction model on the stability of torsion vibrations. A series of experimental tests is performed on a specific test bench to identify the parameters of the driveline and to validate the numerical model. Results shows that the updated numerical model is able to replicate experimental results.

Vibration Monitoring for Local Fault Detection in Synchronous Belts

2008 ◽  
Author(s):  
Roberto Basso ◽  
Giulio Fanti
Keyword(s):  
Numerical Model ◽  
Frequency Spectrum ◽  
Test Bench ◽  
Power Spectra ◽  
Experimental Tests ◽  
Vibration Monitoring ◽  
Signal Acquisition ◽  
Motion Sensors ◽  
Belt Transmission ◽  
Multi Body

The possibility of diagnosing the presence of a fault in a synchronous belt transmission during its work, without dismantling it, by monitoring the vibrations of the pulley support, was investigated in this work. After a few simulations with a multi-body numerical model, several experimental tests were carried out in an apparatus made up of a test bench, motion sensors, a system of signal acquisition and software for data processing. The behavior of mechanical transmissions with healthy and faulty synchronous belts was compared. The damage was simulated by removing a tooth from the belt. The results show that a localized defect on a synchronous belt modifies the frequency spectrum of the motion signals measured on the pulley support. From the experimental tests performed, the following results were obtained: the direction of vibrations measured on the pulley support must be chosen so as to be parallel to the direction of the taut side of the belt; the presence of a defect can be seen in the frequency spectrum by the change in the amplitude of the peaks at the first harmonics of the run frequency; the best condition to highlight the different behaviour in the power spectra occurs when the transmission is under load.

scholarly journals Transient Analysis of the Self Excited Induction Generator Subjected to Grid Disturbances

2015 ◽  
Vol 16 (2) ◽  
pp. 199
Author(s):  
Malika Imadouchene
Keyword(s):  
Numerical Model ◽  
Transient Analysis ◽  
Test Bench ◽  
Numerical Approach ◽  
The Self ◽  
Induction Generator ◽  
Grid Voltage ◽  
Several Variables ◽  
Q Model ◽  
Generator Currents

The present paper analyzes the consequences of short grid voltages interruptions on grid-connected self-induction generator, particularly, on the currents and electromagnetic torque of the generator. These effects depend on several variables such as the phase difference between the grid voltages and those of the generator, the magnitude of the grid voltage and the generator currents at the instant of reconnection to the grid. The approach has been used for studying the effects of these grid disturbances on the self-excited induction generator; is a numerical approach. In the numerical approach, which is based on the dynamic d-q model of the induction generator, the effect of magnetic saturation is accurately accounted for. This numerical model has been validated by experimental measurements taken from an induction generator test bench. The analysis focuses on the amplitudes of the peaks of the currents and torque during short interruptions especially at the reconnection of the grid voltage. The results obtained from the numerical model are compared to the measured ones.

scholarly journals Experimental Research and Computer Simulation of Knock Onset in a Heavy-Duty Si Gas Engine

2019 ◽  
Vol 8 (12) ◽  
pp. 730-736
Keyword(s):  
Boundary Condition ◽  
Numerical Model ◽  
Test Bench ◽  
Combustion Process ◽  
Three Dimensional ◽  
Engine Fuel ◽  
Heavy Duty ◽  
Gas Engine ◽  
Optimization Study ◽  
3D Numerical Model

The work describes the properties of natural gas as a engine fuel, as well as a method for evaluating knocking combustion at a test bench, a 3D numerical model of the combustion process of spark ignited (SI) gas engine and methods for assessing the probability of knocking combustion based on this model. The probability of knocking combustion, which characterizes the boundary condition between normal combustion and knocking, is determined (8%). An optimization study of the influence of adjustment parameters on the probability of knocking based on a three-dimensional numerical model is carried out. The developed and tested technique allows one to monitor the tendency of the influence of various adjustment parameters on the probability of knocking in a SI gas engine

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