MATHEMATICAL MODELING OF THERMOGASDYNAMIC PROCESSES IN PISTON ENGINES

2021 ◽  
pp. 12-17
Author(s):  
A. N. Berdnik ◽  
V. O. Remeslovskiy
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Solitary Waves ◽  
Gas Flow ◽  
Method Of Characteristics ◽  
Finite Amplitude ◽  
Piston Engine ◽  
The Method Of Characteristics ◽  
Turbocharging System ◽  
Calculation Results

A method for calculating the non-stationary gas flow in the exhaust pipeline of a piston engine by the method of solitary waves of finite amplitude is presented. The comparison of experimental data and calculation results by the method of characteristics and obtained when considering the process of propagation of solitary waves through the exhaust pipeline of a piston engine equipped with a pulsed turbocharging system is shown.

scholarly journals Rapid Filling Analysis of Pipelines with Undulating Profiles by the Method of Characteristics

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
A. Malekpour ◽  
B. W. Karney
Keyword(s):  
Experimental Data ◽  
Method Of Characteristics ◽  
Computational Grid ◽  
Filling Process ◽  
Pipe System ◽  
The Method Of Characteristics ◽  
Proposed Model ◽  
Water Conveyance ◽  
Filling Analysis ◽  
Transient Events

On the premise of water hammer theory, a numerical model is proposed for simulating the filling process in an initially empty water conveyance pipeline with an undulating profile. Assuming that the pipeline remains full and ignoring air and water interactions in the already filled pipeline, the ongoing filling is simulated using the method of characteristics on an adaptive computational grid. The performance of the model is verified using previously published experimental and rigid column data. The model nicely replicates published experimental data. The model shows that the movement of the filling front into the system can be assumed as a rigid column as long as the flow away from the filling front is undisturbed elsewhere. Furthermore, applying the model to a hypothetical pipe system with an inline-partially open valve shows that the proposed model is robust enough to capture the transient events initiated within the moving column, a vital capability that the existing rigid water column models lack.

Mathematical Modeling of Ultrasonic Gas Flow Meter Based on Experimental Data in Three Steps

2016 ◽  
Vol 65 (8) ◽  
pp. 1726-1738 ◽  
Author(s):  
Wen-Jiao Zhu ◽  
Ke-Jun Xu ◽  
Min Fang ◽  
Wei Wang ◽  
Zi-Wen Shen
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Gas Flow ◽  
Flow Meter

Research Note: An Alternative Scheme to Solve the Equations for Unsteady Gas Flow

1976 ◽  
Vol 18 (3) ◽  
pp. 161-166
Author(s):  
J. F. T. MacLaren ◽  
A. B. Tramschek ◽  
O. F. Pastrana ◽  
A. Sanjines
Keyword(s):  
Mathematical Models ◽  
Gas Flow ◽  
Method Of Characteristics ◽  
Research Note ◽  
Alternative Scheme ◽  
Flow Equations ◽  
The Method Of Characteristics ◽  
Unsteady Gas Flow ◽  
Engine Systems

A scheme which combines the ‘leap-frog’ method and the method of characteristics was found to be an efficient way to solve the unsteady gas flow equations which form the basis of mathematical models of compressor or engine systems.

scholarly journals Characteristics of mass transfer between gas-liquid phases in a higee reactor

2014 ◽  
Vol 20 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Zhang Zhenzhen ◽  
Guo Kai ◽  
Luo Huijuan ◽  
Song Junnan ◽  
Qian Zhi
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Gas Absorption ◽  
Diffusion Reaction ◽  
Flow Rates ◽  
Rotating Speed ◽  
Liquid Phases ◽  
Calculation Results

In the absorption process of gas-liquid phases in Rotating Packed Bed (RPB), the liquid flow on packing was assumed to be film-flow. Based on Higbie?s penetration theory, the diffusion-reaction model in RPB was introduced to calculate the rate of gas absorption. Taking CO2 (10%)+N2(90%) gas mixture and N-methyldiethanolamine (MDEA) aqueous solution as objects, the experiments of gas absorption were carried out at different gas flow rates, rotating speeds, temperatures, liquid flow rates and MDEA mass concentrations. The experimental data were compared with calculation results to found a good agreement in the rotating speed range of 400-1100r/min. In this range, the rate of decarburization was in direct proportion to rotating speed, temperature and liquid flow rate, and inversely proportion to gas flow rate and MEDA mass concentration. The maximum deviation between experimental data and calculation results was 10%. Beyond the rotating speed of 1100 r/min, the rate of decarburization was dependent on the dynamic balance of gas-liquid system. In this area, the rate of decarburization was inversely proportion to rotating speed.

scholarly journals Stress-deformed state of the shell with a small initial deflection under the action of the end load

2021 ◽  
pp. 67-72
Author(s):  
I. Pozhueva ◽  
Т. Levitskaya
Keyword(s):  
Cylindrical Shell ◽  
Shear Deformation ◽  
Strain State ◽  
Method Of Characteristics ◽  
Initial Deflection ◽  
Stress Strain ◽  
The Method Of Characteristics ◽  
Stress Strain State ◽  
Timoshenko Type ◽  
Calculation Results

Purpose of work. Construction of method for calculating the stress-strain state of cylindrical shell with small initial deflection, to which an end load is applied, using the method of characteristics. Comparison of the calculation results of the obtained model with the works of other authors in this area. Research methods. For the calculation, the equations of motion of the Timoshenko type shell were used, taking into account both the shear deformation and inertia of rotation, and some nonlinear terms, to which the method of characteristics was applied. To obtain the equations of shell motion, the Hamilton-Ostrogradsky variational principle was used. Results method is proposed for calculating the stress-strain state of a cylindrical shell with a small initial deflection using characteristics. Comparative analysis of the calculation results with research in this area by other authors, which showed the effectiveness of the proposed method. Scientific novelty. The equations of the classical theory of shells, based on the Kirchhoff-Love hypotheses, which do not take into account the shear deformation and inertia of rotation, as well as linear equations of the Timoshenko type, have become widespread. In this work, a model of the stress-strain state of an axisymmetric shell with small initial deflections is constructed, taking into account both shear deformation and rotational inertia, and some nonlinear terms. Practical value. The proposed method can be used to calculate the stress-strain state of structures in which thin shells are present as elements, taking into account small initial deflection. This method makes it possible to study the influence of the characteristics of the initial deflection on the stress-strain state of the entire structure.

On the Interaction and Reflection of Shocks in Hyperelastic Strings

1991 ◽  
Vol 58 (2) ◽  
pp. 554-558 ◽  
Author(s):  
J. L. Wegner ◽  
L. Jiang ◽  
J. B. Haddow
Keyword(s):  
Method Of Characteristics ◽  
Numerical Solutions ◽  
Similarity Solutions ◽  
Finite Amplitude ◽  
Governing Equations ◽  
Wave Interactions ◽  
Amplitude Wave ◽  
Multiple Wave ◽  
The Method Of Characteristics ◽  
Interaction Problem

Governing equations for finite amplitude wave propagation in stretched hyperelastic strings are given in recent papers, (Beatty and Haddow, 1985), along with similarity solutions for symmetrically plucked and impacted strings. The similarity solutions are valid until the first reflections at the fixed ends and in this paper we consider symmetrically plucked Mooney-Rivlin strings and investigate the response after reflections. The method of characteristics is applied to extend the results of the similarity solutions and to obtain solutions for the interaction of a reflected longitudinal shock and incident transverse shock and the reflection of an incident transverse shock. A deformed shape, which is not intuitively obvious, is predicted by the solution of the interaction problem and is confirmed by an experimental study. A finite difference scheme is used to obtain numerical solutions, which are valid after multiple wave interactions and reflections occur. Solutions obtained by the method of characteristics are used as a partial check on the numerical results.

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