A Study of the Performance of Inertia Air Filters

1969 ◽  
Vol 184 (3) ◽  
pp. 166-174
Author(s):  
D. E. Gee ◽  
B. N. Cole
Keyword(s):  
Performance Testing ◽  
Operating Conditions ◽  
Design Stage ◽  
Small Scale ◽  
Operating Characteristics ◽  
Test Rig ◽  
Fundamental Study ◽  
Air Filters ◽  
Test Programme ◽  
Wide Range

This paper presents an experimental and theoretical study of the design and performance of inertia air filters, with particular reference to rail traction duty. Using a specially constructed test rig, performance testing of commercially available filters was carried out over a wide range of operating conditions. Subsequently, a more fundamental study of some design variables was carried out in a small-scale test rig. The testing was supported by a theoretical approach using a digital computer model of the inertia filtration process. The results of the work indicate that the inertia filter is suited to high-volume, low pressure drop applications. However, operational difficulties, owing to dust build-up occurring within the filter and variations of bleed ratio, may be encountered. The theoretical model was shown to reproduce all the major operating characteristics of the filters measured in the test programme, and to respond to design changes in a similar way to that indicated by earlier published work. A hypothesis of the mechanism of separation is proposed, and it is suggested that the performance of new filter layouts can be examined at the design stage. Supporting work describes the selection, measurement, and production of a suitable range of polydisperse solids for the test programme.

scholarly journals A broadbanded pressure differential wave energy converter based on dielectric elastomer generators

2021 ◽  
Author(s):  
Michele Righi ◽  
Giacomo Moretti ◽  
David Forehand ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Wave Energy ◽  
Large Deformations ◽  
Dielectric Elastomer ◽  
Wave Energy Converter ◽  
Pressure Differential ◽  
Design Stage ◽  
Small Scale ◽  
Energy Converter ◽  
Wide Range ◽  
The Waves

AbstractDielectric elastomer generators (DEGs) are a promising option for the implementation of affordable and reliable sea wave energy converters (WECs), as they show considerable promise in replacing expensive and inefficient power take-off systems with cheap direct-drive generators. This paper introduces a concept of a pressure differential wave energy converter, equipped with a DEG power take-off operating in direct contact with sea water. The device consists of a closed submerged air chamber, with a fluid-directing duct and a deformable DEG power take-off mounted on its top surface. The DEG is cyclically deformed by wave-induced pressure, thus acting both as the power take-off and as a deformable interface with the waves. This layout allows the partial balancing of the stiffness due to the DEG’s elasticity with the negative hydrostatic stiffness contribution associated with the displacement of the water column on top of the DEG. This feature makes it possible to design devices in which the DEG exhibits large deformations over a wide range of excitation frequencies, potentially achieving large power capture in a wide range of sea states. We propose a modelling approach for the system that relies on potential-flow theory and electroelasticity theory. This model makes it possible to predict the system dynamic response in different operational conditions and it is computationally efficient to perform iterative and repeated simulations, which are required at the design stage of a new WEC. We performed tests on a small-scale prototype in a wave tank with the aim of investigating the fluid–structure interaction between the DEG membrane and the waves in dynamical conditions and validating the numerical model. The experimental results proved that the device exhibits large deformations of the DEG power take-off over a broad range of monochromatic and panchromatic sea states. The proposed model demonstrates good agreement with the experimental data, hence proving its suitability and effectiveness as a design and prediction tool.

scholarly journals Development of the PGT 25 High Efficiency Gas Turbine: Part 2 — Aerodynamic Design and Performance

1984 ◽  
Author(s):  
E. Benvenuti ◽  
B. Innocenti ◽  
R. Modi
Keyword(s):  
Gas Turbine ◽  
High Efficiency ◽  
Performance Testing ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
Direct Drive ◽  
Gas Generator ◽  
Full Load ◽  
Wide Range ◽  
Overall Performance

This paper outlines parameter selection criteria and major procedures used in the PGT 25 gas turbine power spool aerodynamic design; significant results of the shop full-load tests are also illustrated with reference to both overall performance and internal flow-field measurements. A major aero-design objective was established as that of achieving the highest overall performance levels possible with the matching to latest generation aero-derivative gas generators; therefore, high efficiencies were set as a target both for the design point and for a wide range of operating conditions, to optimize the turbine’s uses in mechanical drive applications. Furthermore, the design was developed to reach the performance targets in conjunction with the availability of a nominal shaft speed optimized for the direct drive of pipeline booster centrifugal compressors. The results of the full-load performance testing of the first unit, equipped with a General Electric LM 2500/30 gas generator, showed full attainment of the design objectives; a maximum overall thermal efficiency exceeding 37% at nominal rating and a wide operating flexibility with regard to both efficiency and power were demonstrated.

Subsynchronous Vibration Patterns Under Reduced Oil Supply Flow Rates

2017 ◽  
Author(s):  
B. R. Nichols ◽  
R. L. Fittro ◽  
C. P. Goyne
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Operating Conditions ◽  
System Stability ◽  
Supporting Evidence ◽  
Test Rig ◽  
Flow Rates ◽  
Oil Supply ◽  
Bending Mode ◽  
Wide Range

Many high-speed, rotating machines across a wide range of industrial applications depend on fluid film bearings to provide both static support of the rotor and to introduce stabilizing damping forces into the system through a developed hydrodynamic film wedge. Reduced oil supply flow rate to the bearings can cause cavitation, or a lack of a fully developed film layer, at the leading edge of the bearing pads. Reducing oil flow has the well-documented effects of higher bearing operating temperatures and decreased power losses due to shear forces. While machine efficiency may be improved with reduced lubricant flow, little experimental data on its effects on system stability and performance can be found in the literature. This study looks at overall system performance of a test rig operating under reduced oil supply flow rates by observing steady-state bearing performance indicators and baseline vibrational response of the shaft. The test rig used in this study was designed to be dynamically similar to a high-speed industrial compressor. It consists of a 1.55 m long, flexible rotor supported by two tilting pad bearings with a nominal diameter of 70 mm and a span of 1.2 m. The first bending mode is located at approximately 5,000 rpm. The tiling-pad bearings consist of five pads in a vintage, flooded bearing housing with a length to diameter ratio of 0.75, preload of 0.3, and a load-between-pad configuration. Tests were conducted over a number of operating speeds, ranging from 8,000 to 12,000 rpm, and bearing loads, while systematically reducing the oil supply flow rates provided to the bearings under each condition. For nearly all operating conditions, a low amplitude, broadband subsynchronous vibration pattern was observed in the frequency domain from approximately 0–75 Hz. When the test rig was operated at running speeds above its first bending mode, a distinctive subsynchronous peak emerged from the broadband pattern at approximately half of the running speed and at the first bending mode of the shaft. This vibration signature is often considered a classic sign of rotordynamic instability attributed to oil whip and shaft whirl phenomena. For low and moderate load conditions, the amplitude of this 0.5x subsynchronous peak increased with decreasing oil supply flow rate at all operating speeds. Under the high load condition, the subsynchronous peak was largely attenuated. A discussion on the possible sources of this subsynchronous vibration including self-excited instability and pad flutter forced vibration is provided with supporting evidence from thermoelastohydrodynamic (TEHD) bearing modeling results. Implications of reduced oil supply flow rate on system stability and operational limits are also discussed.

scholarly journals A Novel Hybrid Technique of Frequency Control for Distributed Energy Resources

2021 ◽  
Vol 40 (1) ◽  
pp. 180-204
Author(s):  
Hasham Khan
Keyword(s):  
Power Distribution ◽  
Distribution System ◽  
Energy Demand ◽  
Frequency Control ◽  
Industrial Sector ◽  
Operating Conditions ◽  
Small Scale ◽  
Hybrid Technique ◽  
Operating Characteristics ◽  
Power Distribution System

The rapid increase in the population and fastest development in the industrial sector has increased the energy demand throughout the world. Frequent outages and load shedding has seriously deteriorated the efficiency of the electrical power distribution system. Under such circumstances, the implementation of Distributed Generation (DG) is increasing. Small hydel generators are considered as the most-clean and economical for generating electrical energy. These are very complex nonlinear generators which usually exhibits low frequency electromechanical oscillations due to insufficient damping caused by severe operating conditions. These DGs are not connected to the utility in many cases because, under varying load, they cannot maintain the frequency to the permissible value. This work presents detailed analysis of operating characteristics and proposes a hybrid frequency control strategy of the small hydel systems. The simulation and testing is performed in MATLAB, the results verified the improved performance with the recommended method. The proposed method conserves half of the power consumption. The control scheme regulates the dump load by connecting and disconnecting it affectively. The application of presented methodology is convenient in the deregulated environment, especially under the severe shortage of energy. The proposed model keeps the frequency of system at desired level. It reduces the noise, thereby improving the response time of the designed controller as compared to conventional controllers. The innovative scheme also provides power for small scale industrial, agricultural and other domestic application of far-off areas where the supply of utility main grid is difficult to provide. The recommended scheme is environmental friendly and easy to implement wherever small hydel resources are available.

scholarly journals Modeling in marine ice engineering

2021 ◽  
Vol 11 (4) ◽  
pp. 557-567
Author(s):  
A.A. Dobrodeev ◽  
◽  
K.E. Sazonov ◽  
Keyword(s):  
Modeling And Simulation ◽  
Operating Conditions ◽  
Design Stage ◽  
Modern World ◽  
Marine Structures ◽  
Modeling Methods ◽  
Wide Range ◽  
Comparative Advantages ◽  
Quantitative Results

In the modern world, it is already difficult to imagine the creation of a significant engineering structure without modeling its external and internal appearance, the operation modeling of the main mechanisms, operating conditions and many other design features and emerging phenomena at the design stage. The paper interprets modeling and simulation as one of the computational methods that allow us to obtain quantitative results when studying ice impact on marine structures, for e.g. icebreakers and transport vessels, platform substructures, hydro-technical installations. In connection with the above, from the existing classification of modeling methods, the authors consider the physical and mathematical ones in the work. They present comparative advantages of both methods in their application in the problems of marine ice engineering, as well as the prospects for their development for solving a wide range of scientific problems aimed at the development of Arctic shipbuilding.

Narrower System Reliability Bounds With Incomplete Component Information and Stochastic Process Loading

2017 ◽  
Vol 17 (4) ◽  
Author(s):  
Yao Cheng ◽  
Daniel C. Conrad ◽  
Xiaoping Du
Keyword(s):  
System Reliability ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Stage ◽  
Shared Environment ◽  
Limited Information ◽  
Reliability Bounds ◽  
Component Design ◽  
Wide Range ◽  
Stochastic Load

Incomplete component information may lead to wide bounds for system reliability prediction, making decisions difficult in the system design stage. The missing information is often the component dependence, which is a crucial source for the exact system reliability estimation. Component dependence exists due to the shared environment and operating conditions. But it is difficult for system designers to model component dependence because they may have limited information about component design details if outside suppliers designed and manufactured the components. This research intends to produce narrow system reliability bounds with a new way for system designers to consider the component dependence implicitly and automatically without knowing component design details. The proposed method is applicable for a wide range of applications where the time-dependent system stochastic load is shared by components of the system. Simulation is used to obtain the extreme value of the system load for a given period of time, and optimization is employed to estimate the system reliability bounds, which are narrower than those from the traditional method with independent component assumption and completely dependent component assumption. Examples are provided to demonstrate the proposed method.

Application of Stochastic Optimization Methods in the Gas Turbine Projection Problems

2010 ◽  
Author(s):  
V. E. Afanasjevska ◽  
A. A. Tronchuk ◽  
M. L. Ugryumov
Keyword(s):  
Stochastic Optimization ◽  
Gas Turbine ◽  
Optimization Problems ◽  
Optimization Methods ◽  
Operating Conditions ◽  
Technical System ◽  
Design Stage ◽  
Problem Solution ◽  
Operating Characteristics ◽  
Stochastic Optimization Problem

When projecting the gas turbine an important problem is an ensuring the high values of gas turbine parameters and required gas turbine operating characteristics on the different operating conditions. These requirements can be reached by engine function units system perfecting on base of multicriterion stochastic optimization problems solution. Three stochastic optimization problems definitions were formulated. Each problem has own features and can be used for different application solution. These applied problems are: M-problem can be used on the technical system unit conceptual design stage; V-problem can be used for the problem solution of tolerancing during the technical system unit production; P-problem can be used for interval analysis of technical system functional unit. The multicriterion stochastic optimization problem rational decision is realized by the evolutional method. This method makes it possible to find the solution with given accuracy by attraction the less information recourses than standard methods. In the stochastic optimization problems definitions the input data random character is taken into account. It makes it possible to find the optimal values of desired parameters. These parameters ensure the maximal probability of finding the objective function in given range.

scholarly journals Modeling of Some Operating Parameters Required for the Development of Fixed Bed Small Scale Pyrolysis Plant

Resources ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 79 ◽  
Author(s):  
Bacskai ◽  
Madar ◽  
Fogarassy ◽  
Toth
Keyword(s):  
Fixed Bed ◽  
Gas Production ◽  
Design Stage ◽  
Small Scale ◽  
Material Structure ◽  
Mathematical Function ◽  
Operating Characteristics ◽  
Biomass Waste ◽  
Experimental Apparatus ◽  
Pyrolysis Unit

In recent years, we have read a lot of research aimed at creating a small, easy-to-mobilize pyrolysis unit. But these devices were not efficiently designed. According to literature data, small equipment (5.0–50 kW) has to be considered differently on the combustion aspects, compared to a larger pyrolysis unit. The main purpose of our research is to determine the operating characteristics of a small fixed bedding CHP (combined heat and power) pyrolysis power plant. At the design stage, it is also critical to know the properties of the biomass (usually different biological wastes) used on the input side. The use of a wide diversity of biomass waste may result in the volume of material remains and the energy produced is not usable in the right form. To obtain a clear picture of the combustion conditions, a fixed bedding pilot pyrolysis device was made. With the measurements in the experimental apparatus, we have a clearer picture of the changes in some of combustion parameters. We have examined exactly how the size and hardness of biomass materials affect the efficiency of pyrolysis. By modelling the “mass change”—with the knowledge of the material content, physical characteristics, and the parameters of the pyrolysis equipment—the amount of the expected material remains, and combustion conditions can be predicted with a mathematical function. We have found an appropriate mathematical model (R2 = 0.8758) to describe the relationship between gas production and material structure for a given period.

Design of Small Centrifugal Compressors Performance Test Facility

2004 ◽  
Author(s):  
Fahad A. Al-Sulaiman ◽  
Amro M. Al-Qutub
Keyword(s):  
Performance Test ◽  
Performance Testing ◽  
Selection Procedure ◽  
Power Input ◽  
Test Facility ◽  
Design Stage ◽  
Centrifugal Compressors ◽  
Drive Unit ◽  
Actual Performance ◽  
Wide Range

Actual performance testing is a key element in the design stage, development and troubleshooting of centrifugal compressors. The present work discusses the procedure for designing the experimental setup and the selection of drive unit for variable centrifugal compressors sizes. It starts with setting criteria of selection. A survey over different types of drive units and facility setup was conducted. It was found that the electric drive unit with the aid of transmission for stepping-up the speeds is the most suitable type. This is due mainly to the excellent control property of electric motors allowing for wide range of operational speed and power. A new methodology was developed for selecting operational power and speeds of the drive unit for different sizes of impellers. The code, used for the analysis, was developed by the authors. It calculates the range of input power, input torque, and rotational speeds, as well as, the mass flow rate, total pressure and temperature ratios for different sizes of impellers. This will aid in selecting the proper instrumentation for the experiments. The code used for design methodology is based on one dimensional through flow formulation and validated with experimental results in the literature. It is expected that the present methodology will enhance selection procedure for designing compressor test facility.

Predicting Heat Transfer From Unsteady Synthetic Jets

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Mehmet Arik ◽  
Tunc Icoz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Jet Impingement ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Operating Conditions ◽  
Small Scale ◽  
Wide Range ◽  
The Heat Transfer Coefficient

Synthetic jets are piezo-driven, small-scale, pulsating devices capable of producing highly turbulent jets formed by periodic entrainment and expulsion of the fluid in which they are embedded. The compactness of these devices accompanied by high air velocities provides an exciting opportunity to significantly reduce the size of thermal management systems in electronic packages. A number of researchers have shown the implementations of synthetic jets on heat transfer applications; however, there exists no correlation to analytically predict the heat transfer coefficient for such applications. A closed form correlation was developed to predict the heat transfer coefficient as a function of jet geometry, position, and operating conditions for impinging flow based on experimental data. The proposed correlation was shown to predict the synthetic jet impingement heat transfer within 25% accuracy for a wide range of operating conditions and geometrical variables.

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