scholarly journals Distribution of piston compression ring pressure against the deformed cylinder wall

2011 ◽  
Vol 145 (2) ◽  
pp. 17-24
Author(s):  
Wojciech SERDECKI ◽  
Piotr KRZYMIEŃ
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Wall Pressure ◽  
Cylinder Wall ◽  
Compression Ring ◽  
Cylinder Diameter ◽  
Medium Speed ◽  
Light Gaps

The following study presents typical cylinder deformations that come up during engine assembly and operation and provides results of analysis of how these changes affect the operation of the compression ring. Special attention has been paid to the effect of cylinder diameter increase on the distribution of the circumferential wall pressure and the cause of light gaps formation has been explained. The analyses presented in the following paper have been carried out using a computer program that has been formulated based on a compression ring mathematical model. Exemplary results of simulation have been obtained for a medium speed generator engine of a cylinder diameter of 0.48 m.

scholarly journals An analysis of phenomena accompanying ring collaboration with worn cylinder surface

2013 ◽  
Vol 153 (2) ◽  
pp. 40-47
Author(s):  
Wojciech SERDECKI ◽  
Piotr KRZYMIEŃ
Keyword(s):  
Mathematical Description ◽  
Wall Pressure ◽  
Cylinder Surface ◽  
Cylinder Wall ◽  
Compression Ring ◽  
Wall Deformation ◽  
Definition Of ◽  
Circumferential Pressure

The presented study which refers to the earlier papers of the authors discusses an effect of cylinder wall deformation on the effectiveness of compression ring operation. Presented models permit a mathematical description of a deformed cylinder and definition of ring wall pressure relative to these deformations. The drafts presented in the paper, obtained in a course of calculations of a compression ring installed in a work machine engine, allow to evaluate the effect of cylinder deformations on distribution of ring circumferential pressure and point out areas where the light slots could occur.

The lake ecosystem simulation program

1995 ◽  
Vol 31 (8) ◽  
pp. 367-370
Author(s):  
J. Heringa ◽  
H. Hylkema ◽  
M. Kroes ◽  
E. Ludden ◽  
P. G. van Schaick Zillesen
Keyword(s):  
Mathematical Model ◽  
Water Resources ◽  
Computer Program ◽  
Water Resources Management ◽  
Lake Ecosystem ◽  
Original Research ◽  
Ecological Processes ◽  
Resources Management ◽  
Lake Ecology ◽  
Ecosystem Simulation

The computer program LAKE simulates a shallow lake ecosystem. The program is based on a mathematical model. In the model the most important aspects of several models for water resources management are integrated (Collins and Wlosinski, 1988; Jørgensen, 1976; Jørgensen et al., 1978; Scheffer, 1988). Furthermore, the model describes several ecological processes that have not yet been described by lake-ecosystem models so far. In the computer program, the mathematical model and an advanced, object oriented, user interface are combined. Following this approach the use of the original research models was extended to a use for the purpose of teaching lake ecology. We suggest that the same approach may be followed to open research models to other groups concerned with water resources management, such as management authorities, industry, agricultural extension, nature conservation and recreation.

The Automatic Generation of a Mathematical Model for Machinery Systems

1973 ◽  
Vol 95 (2) ◽  
pp. 629-635 ◽  
Author(s):  
D. A. Smith ◽  
M. A. Chace ◽  
A. C. Rubens
Keyword(s):  
Mathematical Model ◽  
Graph Theory ◽  
Computer Program ◽  
Mechanical System ◽  
Input Data ◽  
Automatic Generation ◽  
Electrical Networks ◽  
Lagrange’S Equation ◽  
Detailed Explanation ◽  
Independent Loops

This paper presents a detailed explanation of a technique for automatically generating a mathematical model for machinery systems. The process starts from a relatively small amount of input data and develops the information required to model a mechanical system with Lagrange’s equation. The technique uses elements of graph theory which were developed for electrical networks. The basic identifications required for mechanical systems are: paths from ground to mass centers, the independent loops of parts, if any, and paths associated with applied force effects. The techniques described in this paper have been used successfully in a generalized computer program, DAMN.

scholarly journals STUDY, DESIGN AND SIMULATION OF A PROGRAM FOR NUMERICAL EVALUATION OF VEHICLES’ FUEL CONSUMPTION DUE TO DRAG FORCE; CASE OF LIGHT VEHICLES.

2020 ◽  
Vol 7 (1) ◽  
pp. 1-11
Author(s):  
Mbelle Samuel Bisong ◽  
Paune Felix ◽  
Lokoue D. Romaric Brandon ◽  
Pierre Kisito Talla
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Fuel Consumption ◽  
Drag Force ◽  
Numerical Evaluation ◽  
Construction Companies ◽  
Mathematical Relation ◽  
Basic Equations ◽  
Valid Information

Nowadays, vehicles are being abandoned by their users due to their high fuel consumption which had not been studied by the user from the start. Thus, the need to study the fuel consumption of vehicles due to one of the factors which greatly affects it; drag force, so as to produce information which vehicle users can have before purchasing their vehicles. With regards to this, this work is focused on the development of a computer program able to evaluate the fuel consumption of light vehicles. To achieve this, the basic equations of consumption are used to arrive at a mathematical relation between drag force and fuel consumption. This mathematical model is further implemented on the analytical software Matlab in order to produce the various consumption curves of the vehicles case study. A simulator which takes into consideration a vehicle’s engine data in order to produce specific consumption curves and provide valid information on the fuel consumption of the vehicle is developed from this mathematical model. It can be used in automotive construction companies and also by any individual.

scholarly journals SYNTHESIS OF PROGRAM AND FINITE LAWS OF MOTION IN ANALYTICAL MODELS OF CONTROL OF THE FINAL STATE OF BIOMECHANICAL SYSTEMS

2019 ◽  
Vol 19 (1) ◽  
pp. 93-99
Author(s):  
V Zagrevskiy ◽  
O Zagrevskiy
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Center Of Mass ◽  
Material Point ◽  
Object Motion ◽  
Reference Points ◽  
Analytical Models ◽  
Final State ◽  
Finite Control ◽  
The Mathematical Model

Aim. The article deals with developing a computer program to simulate the movement of the object with a given initial and final speed and fixed travel time. Materials and methods. The analysis, as a method of biomechanics, allows us to assess the biomechanical state of the athlete in real sports exercises. The function of motion synthesis is the ability to predict the trajectory and behavior of the biomechanical system at specified reference points of the phase structure of the simulated motion. The article deals with one of the methods of biomechanical synthesis of movements: synthesis of control of the final state of biomechanical systems, based on the reduction of finite control to a given program control after attenuation of the transient component of acceleration. The mathematical description of the object motion is based on the known law of finite control with feedback. Integration of the mathematical model constructed in the form of the differential equation of the second order was carried out by one of the numerical methods of integration: Runge–Kutta method of the fourth order of accuracy. Consideration of the method is based on a mathematical apparatus describing the motion of a material point, which can be represented by a common center of mass of a biomechanical system, a joint, a center of mass of a segment, etc. Results. The mathematical model of the motion of a material point with the given kinematic parameters of motion at the initial and final moments is implemented in a computer program in the Visual Basic 2010 language environment based on the integrated development environment Visual Studio Express 2013. The output provides numerical and visual support for simulation results. Conclusion. It is shown that the developed computer model of the method always implements the goal of motion: to transfer an object from a given initial state by speed to a given final state for a fixed time of movement.

Analysis of the Combustion Air Preheater from the Aluminum Melting Furnaces

2016 ◽  
Vol 14 (11) ◽  
pp. 27-32
Author(s):  
Aurel Gaba ◽  
Vasile Bratu ◽  
Dorian Musat ◽  
Ileana Nicoleta Popescu ◽  
Maria Cristiana Enescu
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Computer Program ◽  
Flue Gas ◽  
Heat Recovery ◽  
Melting Furnace ◽  
Operating Conditions ◽  
Air Preheater ◽  
Constructive Version ◽  
Scrap Aluminum

Abstract This paper presents solutions and the equipment for preheating combustion air from scrap aluminum melting furnaces through flue gas heat recovery. For sizing convection pre-heaters, there has been developed a mathematical model which has been transcribed into a computer program in C + +. A constructive version of the pre-heater was drawn up and a recovery heat exchanger was manufactured and mounted on an aluminum melting furnace. Both the functional parameters values and the reasons causing the pre-heater worning out, as well as the steps taken for sizing and the achievement of a new air pre-heater able to bear the operating conditions of the aluminum melting furnace are shown.

A Study of Transient Response of Flexible Rotors in High Speed Turbomachinery

1992 ◽  
Author(s):  
V. Pavelic ◽  
R. S. Amano
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Analytical Model ◽  
High Speed ◽  
Angular Speed ◽  
Journal Bearings ◽  
Hydrodynamic Characteristics ◽  
Flexible Assembly ◽  
Lagrange’S Equation ◽  
Equations Of Motions

In many applications the design operating range of the turbomachinery may be well above the rotor first critical speed which leads to the problem of insuring that the turbomachinery performs with a stable, low-level amplitude of vibration. Under certain conditions of high speed and loading the rotor system can start orbiting in its bearing at a rate which is less than the rotor angular speed, and this phenomena is commonly known as whirling or whipping action. This whipping action may produce additional undesirable dynamic loads on the overall flexible assembly and eventually destroy the rotor. Some of this action is also transient in nature. Whirling is a self-exited vibration caused mainly by the fluid bearings and by the internal friction damping of the rotor. To understand this occurrence, a general dynamic mathematical model was derived considering also the complete viscous characteristic of hydrodynamic journal bearings. The general equations of motions of the system are obtained from Lagrange’s equation of motion. The system kinetic, potential, and dissipation functions are determined based on the generalized coordinates of the system. The journal displacements are related to the overall dynamics of the rotor using deformable bearings. The loads acting at the journals of the shaft are integrated from the fluid film pressure distribution in the journal bearings using mobility method. A unique mathematical model is formulated and solved. This model includes the elastic and inertial properties of the flexible rotor, the elastic, damping and inertial properties of supports and the hydrodynamic characteristics of the journal bearings. The equations of motions result in a system of nonlinear second order differential equations which are solved by using finite difference method. The solution of the equations of motions is used to plot maps of motion of journal centers. A computer program was implemented to aid in the solution of the system of equations and to verify analytical model. The computer program used test data available in literature and the results were compared to be very good. The analytical model and results obtained in this study can be of great help to designers of high speed turbomachinery.

Multidimensional Modeling and Validation of Dual-Fuel Combustion in a Large Bore Medium Speed Diesel Engine

2015 ◽  
Author(s):  
Sameera Wijeyakulasuriya ◽  
Ravichandra S. Jupudi ◽  
Shawn Givler ◽  
Roy J. Primus ◽  
Adam E. Klingbeil ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Adaptive Mesh Refinement ◽  
Computational Cost ◽  
Adaptive Mesh ◽  
Cylinder Wall ◽  
Detailed Chemical Kinetics ◽  
Substitution Rates ◽  
Numerical Predictions ◽  
Medium Speed

High fidelity, three-dimensional CFD was used to model the flow, fuel injection, combustion, and emissions in a large bore medium speed diesel engine with different levels of natural gas substitution. Detailed chemical kinetics was used to model the complex combustion behavior of the premixed natural gas, ignited via a diesel spray. The numerical predictions were compared against measured multiple cycle pressure data, to understand the possible factors affecting cyclic variation in experimental data. Under conditions with high natural gas substitution rates, diesel was injected much earlier than firing-TDC. This additional mixing time allowed the active radicals from diesel dissociation to initiate combustion from the cylinder wall and propagate inwards. 0%, 60%, and 93% natural gas substitution rates (by energy) were tested in this study to develop computational capabilities needed to accurately model and understand the underlying physics. Several innovative computational methods such as adaptive mesh refinement (which automatically refines and coarsens the mesh based on the existing solution parameters), and multi-zoning (which groups chemically similar cells together to reduce combustion calculation time) were utilized to obtain accurate predictions at a lower computational cost. Important engine emissions such as NOx, CO, unburnt HC, and soot were predicted numerically and compared against measured engine data.

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