scholarly journals Efflux through a circular orifice

1944 ◽  
Vol 182 (991) ◽  
pp. 347-361 ◽  
Keyword(s):  
Steady State ◽  
Internal Combustion Engines ◽  
Electric Circuit ◽  
Power Input ◽  
Visual Observation ◽  
Combustion Engines ◽  
Resonance Frequencies ◽  
Wide Range ◽  
Flow Phenomena ◽  
Flow Through

The purpose of this research was the establishment of the law of efflux from a vessel under pressure through a suddenly opened orifice of comparatively large dimensions. In order to simplify the approach to the problem, it was decided to investigate the efflux of an incompressible fluid, e.g. water. The methods of approach were based on analogies with electric circuit theory, and accordingly an apparatus was built in which the equivalent of a.c. experiments with resonant circuits could be performed. An orifice in the apparatus represented the inertia in the resonant system . Acoustic theory gives the inertance of such an orifice for infinitesimal amplitudes. In the experiments described, this inertance was measured at a wide range of finite amplitudes, by observations of phase shift between power input and displacement at the orifice. By this means it was possible to determine the exact resonance frequencies of the hydraulic system in spite of its high damping. By this means, the effective mass or inertance of the fluid flowing through the orifice was deduced. In the course of these experiments some interesting flow phenomena, to the author’s knowledge not previously recorded, were observed and photographed. There appear to be three distinct modes of flow, as compared with the two commonly observed in the steady state. The contraction coefficient of the flow through the orifice was found to be unity for small amplitudes and to approach the steady state value for large amplitudes. The differential equation of the efflux through a suddenly opened orifice is stated and its solution given. A numerical example is worked out with the constants derived from measurements and the results are shown by graphs. They were checked by visual observation though a recording of the efflux experiment was not found possible. It can be seen that a suction effect must follow a discharge. Further that this suction and the following oscillations are practically independent of the pressure in the vessel before the discharge, provided this pressure is above a certain value. These findings are of interest in connexion with the exhaust phenomena in internal combustion engines, in particular those working on the two-stroke cycle.

scholarly journals Fuel Cells: The Next Evolution

MRS Bulletin ◽  
2005 ◽  
Vol 30 (8) ◽  
pp. 581-586 ◽  
Author(s):  
Robert W. Lashway
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Internal Combustion Engines ◽  
Materials Science ◽  
Electrical Conductance ◽  
Electrical Energy ◽  
Pure Oxygen ◽  
Combustion Engines ◽  
Hydrogen Fuel ◽  
Wide Range

AbstractThe articles in this issue of MRS Bulletin highlight the enormous potential of fuel cells for generating electricity using multiple fuels and crossing a wide range of applications. Fuel cells convert chemical energy directly into electrical energy, and as a powergeneration module, they can be viewed as a continuously operating battery.They take in air (or pure oxygen, for aerospace or undersea applications) and hydrocarbon or hydrogen fuel to produce direct current at various outputs. The electrical output can be converted and then connected to motors to generate much cleaner and more fuelefficient power than is possible from internal combustion engines, even when combined with electrical generators in today's hybrid engines. The commercialization of these fuel cell technologies is contingent upon additional advances in materials science that will suit the aggressive electrochemical environment of fuel cells (i.e., both reducing an oxidizing) and provide ionic and electrical conductance for thousands of hours of operation.

A Theoretical Approach to the Combustion of Fuel-Alcohol Blends

1985 ◽  
Vol 107 (4) ◽  
pp. 902-907 ◽  
Author(s):  
G. Cau ◽  
M. P. Pelagagge
Keyword(s):  
Total Energy ◽  
Theoretical Investigation ◽  
Theoretical Approach ◽  
Total Mass ◽  
Internal Combustion Engines ◽  
Combustion Temperature ◽  
Analytical Procedure ◽  
Combustion Engines ◽  
Constant Mass ◽  
Wide Range

This paper is concerned with the results of a theoretical investigation on combustion of traditional fuel and alcohol blends. An analytical procedure has been developed which examines three different hypotheses for introducing the alcohol: constant mass of primary fuel, constant total energy of fuel, and constant total mass of fuel. The procedure has been applied to combustion at constant volume varying over a wide range of air-fuel ratios, percentage of alcohol, and combustion temperature. The results obtained, of particular interest for reciprocating internal combustion engines, indicate that as far as energy and emissions are concerned, the effects of alcohol on combustion depend strongly on the hypothesis adopted for fueling the alcohol.

Impact of a Holistic Turbocharger Model in the Prediction of Engines Performance in Transient Operation and in Steady State With LP-EGR

2018 ◽  
Author(s):  
José Ramón Serrano ◽  
Francisco José Arnau ◽  
Luis Miguel García-Cuevas González ◽  
Alejandro Gómez-Vilanova ◽  
Stephane Guilain
Keyword(s):  
Steady State ◽  
Internal Combustion Engines ◽  
Inlet Temperature ◽  
Detailed Calculation ◽  
Combustion Engines ◽  
Reciprocating Engine ◽  
Steady State Operation ◽  
And Performance ◽  
Source Of Information ◽  
Optimization And Performance

Turbocharged engines are the standard powertrain type of internal combustion engines for both spark ignition and compression ignition concepts. Turbochargers modeling traditionally rely in look up tables based on turbocharger manufacturer provided maps. These maps as the only secure source of information. They are used both for the matching between reciprocating engine and the turbocharger and for the further engine optimization and performance analysis. In the last years have become evident that only these maps are not being useful for detailed calculation of variables like after-treatment inlet temperature (turbine outlet), intercooler inlet temperature (compressor outlet) and engine BSFC at low loads. This paper shows a comprehensive study that quantifies the errors of using just look up tables compared with a model that accounts for friction losses, heat transfer and gas-dynamics in a turbocharger and in a conjugated way. The study is based in an Euro 5 engine operating in load transient conditions and using a LP-EGR circuit during steady state operation.

Calculation and Optimization of Tribocontacts and Lubrication Systems of Internal Combustion Engines for Various Types of Lubricant

2005 ◽  
Author(s):  
S. Sivrikova ◽  
J. Rojdestvensky ◽  
I. Petrov ◽  
S. Popova
Keyword(s):  
Steady State ◽  
Internal Combustion Engines ◽  
Fuel Efficiency ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Lubrication System ◽  
Optimum Choice ◽  
Transient And Steady State

Quality, reliability and fuel efficiency of internal combustion engines (ICE) substantially depend upon optimum choice of lubrication system and tribocontact design and a lubricant liquid. This paper describes a quasistatic method of analysis of ICE lubrication systems for Newtonian and non-Newtonian oils. The method allows for both transient and steady-state conditions.

scholarly journals A design tool for the performances comparison of innovative energy systems for naval applications

2019 ◽  
Vol 113 ◽  
pp. 02005
Author(s):  
D. Rattazzi ◽  
M. Rivarolo ◽  
T. Lamberti ◽  
L. Magistri
Keyword(s):  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Energy Systems ◽  
Design Tool ◽  
Pollutant Emissions ◽  
Combustion Engines ◽  
Wide Range ◽  
Storage Technologies ◽  
Market Solutions ◽  
And Storage

This paper aims to develop a tool for the performances comparison of innovative energy systems on board ships, both for concentrated and distributed generation applications. In the first part of the study, the tool database has been developed throughout a wide analysis of the available market solutions in terms of energy generation devices (i.e. fuel cells, internal combustion engines, micro gas turbines), fuels (hydrogen, natural gas, diesel) and related storage technologies. Many of these data have been collected also thanks to the laboratory experience of the authors’ research group on different innovative energy systems. From the database, a wide range of maps has been created, correlating costs, volumes, weights and emissions with the installed power and the operational hours required, given by the user as input. The tool highlights the best solution according to the different relevance chosen by the user for each key parameter (i.e. costs, volumes, emissions). In the second part, two different case studies are presented in order to underline how the installed power, the different ship typology and the user requirements affect the choice of the best solution. It is worth noting that the methodology has a general value, as the tool can be applied to both the design of new ships, and to the retrofit of already existing ships in order to respect new requirements (e.g. more and more stringent normative in terms of pollutant emissions in ports and restricted areas). Furthermore, the database can be easily extended to other generation and storage technologies.

scholarly journals Energetic Analysis of the Aircraft Diesel Engine

2019 ◽  
Vol 252 ◽  
pp. 05012
Author(s):  
Łukasz Grabowski ◽  
Konrad Pietrykowski ◽  
Paweł Karpiński
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Energy Balance ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Energy Losses ◽  
Exhaust Gas ◽  
Combustion Engines ◽  
Engine Model ◽  
Energetic Analysis

The analysis of the distribution of thermal energy generated during the combustion process in internal combustion engines and the estimation of individual losses are important regarding performance and efficiency. The article analyses the energy balance of the designed two-stroke opposed piston diesel engines with offset, i.e. the angle by which the crankshaft at the side of exhaust ports is ahead of the crankshaft at the side of intake ports. Based on the developed zero-dimensional engine model, a series of simulations were performed in steady-state conditions using the AVL BOOST software. The values of individual energy losses, including cooling losses, exhaust gas losses, friction losses were obtained. The influence of decreasing and increasing the offset on the performance of the tested engine was analysed.

Prediction of the steady and non-steady flow performance of a highly loaded mixed flow turbine

1998 ◽  
Vol 212 (3) ◽  
pp. 173-184 ◽  
Author(s):  
M Abidat ◽  
M Hachemi ◽  
M K Hamidou ◽  
N C Baines
Keyword(s):  
Steady State ◽  
Performance Prediction ◽  
Internal Combustion Engines ◽  
Prediction Method ◽  
Combustion Engines ◽  
Steady State Flow ◽  
Mixed Flow ◽  
One Dimensional ◽  
Flow Equations ◽  
State Flow

This paper describes a method for predicting the performance under both turbine inlet steady state and non-steady state flow conditions of a mixed flow turbine used for turbocharged internal combustion engines. The mixed flow turbine steady state performances computed with the steady state performance prediction method are in good agreement with the experimental results obtained in the Imperial College turbocompressor cold air test rig. The unsteady state performance is computed using a one-dimensional model based on the solution of the unsteady one-dimensional flow equations. These equations are solved in the volute by a finite difference method using a four-step explicit Runge—Kutta scheme. The instantaneous volute exit condition is provided by the steady state rotor performance prediction model with the assumption of a quasi-steady state flow in the rotor. The computed instantaneous performances are in reasonable agreement with published experimental data for the same mixed flow turbine. The unsteady flow model is also used to study the effects of the frequency and the amplitude of the pulse on the performances of the mixed flow turbine.

Non-Steady Flow through a Gauze in a Duct

1965 ◽  
Vol 7 (4) ◽  
pp. 449-459 ◽  
Author(s):  
R. S. Benson ◽  
P. C. Baruah
Keyword(s):  
Steady Flow ◽  
Excellent Agreement ◽  
Pressure Loss ◽  
Internal Combustion Engines ◽  
Wave Action ◽  
Combustion Engines ◽  
Flow Through ◽  
Flow Pressure ◽  
Loss Coefficients ◽  
Flow Experiments

By using steady flow relations including pressure loss coefficients a method is developed for calculating wave action in a duct with a gauze. Both steady and non-steady flow experiments for five gauzes are described. The results of the non-steady flow tests showed excellent agreement between the predicted indicator diagrams, using the steady flow pressure loss coefficients, and the measured indicator diagrams. The methods described in the paper may be used by engine designers to predict the effect of gauzes or similar devices on the wave action in exhaust systems of internal combustion engines.

Intake Air Path Diagnostics for Internal Combustion Engines

2006 ◽  
Vol 129 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Matthew A. Franchek ◽  
Patrick J. Buehler ◽  
Imad Makki
Keyword(s):  
Steady State ◽  
Internal Combustion Engines ◽  
Air Flow ◽  
Internal Combustion ◽  
Flow Sensor ◽  
Path Model ◽  
Intake Manifold ◽  
Fault Estimation ◽  
Combustion Engines ◽  
Sensor Measurement

Presented is the detection, isolation, and estimation of faults that occur in the intake air path of internal combustion engines during steady state operation. The proposed diagnostic approach is based on a static air path model, which is adapted online such that the model output matches the measured output during steady state conditions. The resulting changes in the model coefficients create a vector whose magnitude and direction are used for fault detection and isolation. Fault estimation is realized by analyzing the residual between the actual sensor measurement and the output of the original (i.e., healthy) model. To identify the structure of the steady state air path model a process called system probing is developed. The proposed diagnostics algorithm is experimentally validated on the intake air path of a Ford 4.6L V-8 engine. The specific faults to be identified include two of the most problematic faults that degrade the performance of transient fueling controllers: bias in the mass air flow sensor and a leak in the intake manifold. The selected model inputs include throttle position and engine speed, and the output is the mass air flow sensor measurement.

scholarly journals Development and Validation of a Reduced DME Mechanism Applicable to Various Combustion Modes in Internal Combustion Engines

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Gregory T. Chin ◽  
J.-Y. Chen ◽  
Vi H. Rapp ◽  
R. W. Dibble
Keyword(s):  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Detailed Mechanism ◽  
Reduced Mechanism ◽  
Hcci Combustion ◽  
Combustion Modes ◽  
Reduced Chemistry ◽  
Wide Range ◽  
Development And Validation

A 28-species reduced chemistry mechanism for Dimethyl Ether (DME) combustion is developed on the basis of a recent detailed mechanism by Zhao et al. (2008). The construction of reduced chemistry was carried out with automatic algorithms incorporating newly developed strategies. The performance of the reduced mechanism is assessed over a wide range of combustion conditions anticipated to occur in future advanced piston internal combustion engines, such as HCCI, SAHCCI, and PCCI. Overall, the reduced chemistry gives results in good agreement with those from the detailed mechanism for all the combustion modes tested. While the detailed mechanism by Zhao et al. (2008) shows reasonable agreement with the shock tube autoignition delay data, the detailed mechanism requires further improvement in order to better predict HCCI combustion under engine conditions.

Sign in / Sign up

Export Citation Format

Share Document