scholarly journals Virtual Indication of the Torque for a Marine Gas Turbine

2021 ◽  
Vol 3 (10) ◽  
pp. 74-81
Author(s):  
Filip Niculescu ◽  
Mirela Letitia Vasile ◽  
George Balan ◽  
Adrian Săvescu ◽  
Roxana Nicolae
Keyword(s):  
Mathematical Model ◽  
Gas Turbines ◽  
Test Bench ◽  
Sampled Data ◽  
Control Software ◽  
Software Application ◽  
Marine Applications ◽  
Engine Size ◽  
Propulsion Power ◽  
Engine Power

Gas turbines are used in marine applications where high propulsion power is required compared to engine size and mass. In some cases, the torque and engine power developed cannot be measured with a special transducer implemented in applications or if there are indications, they need to be compared with the calculated torque indication. For this purpose, we developed in the engine control software application a mathematical model for calculating and displaying the torque and power developed by the engine. Through comparisons in the tests with the engine on the test bench, this mathematical model was refined. At this time the comparative sampled data can be used as a virtual indication of torque in cases where this is necessary.

A MATHEMATICAL MODEL OF THE PHYSICAL GROWTH MECHANISM AND GEOMETRICAL CHARACTERIZATION OF GROWING FORMS

2011 ◽  
Vol 04 (01) ◽  
pp. 35-53 ◽  
Author(s):  
YURI K. SHESTOPALOFF
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Growth Mechanism ◽  
Growth Suppression ◽  
Physical Growth ◽  
Geometrical Parameters ◽  
Growth Equation ◽  
Software Application ◽  
Multicellular Organisms

The article introduces a mathematical model of the physical growth mechanism which is based on the relationships of the physical and geometrical parameters of the growing object, in particular its surface and volume. This growth mechanism works in cooperation with the biochemical and other growth factors. We use the growth equation, which mathematically describes this mechanism, and study its adequacy to real growth phenomena. The growth model very accurately fits experimental data on growth of Amoeba, Schizosaccharomyces pombe, E.coli. Study discovered a new growth suppression mechanism created by certain geometry of the growing object. This result was proved by experimental data. The existence of the growth suppression phenomenon confirms the real workings and universality of the growth mechanism and the adequacy of its mathematical description. The introduced equation is also applicable to the growth of multicellular organisms and tumors. Another important result is that the growth equation introduces mathematical characterization of geometrical forms that can biologically grow. The material is supported by software application, which is released to public domain.

scholarly journals Effect of the Harmonic Voltage Distortion on the Efficiency of a Compact Fluorescent Lamp

2020 ◽  
Vol 29 (54) ◽  
pp. e11604
Author(s):  
Esteban Rojas-Osorio ◽  
Andrés Julián Saavedra-Montes ◽  
Carlos Andrés Ramos-Paja
Keyword(s):  
Mathematical Model ◽  
Test Bench ◽  
Harmonic Distortion ◽  
Fluorescent Lamp ◽  
Constant Frequency ◽  
Voltage Distortion ◽  
Variable Voltage ◽  
Harmonic Voltage ◽  
Compact Fluorescent Lamp ◽  
Harmonic Components

This paper evaluates the effect of the voltage harmonic distortion over the efficiency of a compact fluorescent lamp that is fed with a constant RMS voltage and constant frequency. Several works have been published about the assessment of compact fluorescent lamps, but the effect of the voltage distortion over the efficiency is still an open topic. This work focuses on designing an experiment to estimate the efficiency of a compact fluorescent lamp while changing the voltage harmonic distortion of the power supply. First, a mathematical model that represents a bus susceptible to harmonic distortion (high impedance) that feeds the compact fluorescent lamp is analyzed. Then the mathematical model is reproduced through a test bench in a laboratory of rotating electrical machines. The test bench produces a three-phase bus with constant voltage and frequency, and variable voltage harmonic distortion. The compact fluorescent lamp is subjected to varying harmonic voltage distortion while recording its electrical variables and the produced lumens to estimate its efficiency. That is a practical approach to calculate the lamp efficiency while several works limit their scope measuring only the efficiency of the input converter. The experimental results show that a variation of the voltage harmonic distortion of 8 % on a compact fluorescent lamp reduces its efficiency. Those results put into evidence the importance of regulating harmonic distortion limits to reduce or prevent the increment of power losses caused by harmonic components.

scholarly journals A virtual test bench for determining the loads in the air suspension of the rear trolley of a truck at the early stages of design

2021 ◽  
Vol 1 (3) ◽  
pp. 76-86
Author(s):  
R.O. Maksimov ◽  
◽  
I.V. Chichekin ◽  
Keyword(s):  
Mathematical Model ◽  
Test Bench ◽  
Software Tools ◽  
Rigid Bodies ◽  
Virtual Test ◽  
Early Stages ◽  
Air Suspension ◽  
Solid Suspension ◽  
Suspension Model ◽  
Standard Software

To determine the maximum loads acting in the rear air suspension of a truck at the early stages of design there was used computer modeling based on solving equations of dynamics of solids and implemented in the Recurdyn software. The components of the developed virtual test bench, includ-ing hinges, power connections, drive axles, a wheel-hub assembly with a wheel and a support plat-form, are considered in detail. The test bench is controlled using a mathematical model created in the environment for calculating the dynamics of rigid bodies and associated with a solid suspension model by standard software tools of the application. The test bench is controlled using a mathemati-cal model created in the environment for calculating the dynamics of rigid bodies and associated with a solid suspension model by standard software tools of the application. The use of such a test bench makes it possible to determine the loads in the hinges and power connections of the suspen-sion, to determine the mutual positions of the links for each load mode, to increase the accuracy of the calculation of loads in comparison with the flat kinematic and force calculation. The mathemati-cal model of the virtual test bench allows to carry out numerous parametric studies of the suspension without the involvement of expensive full-scale prototypes. This makes it possible at the early stages of design to determine all hazardous modes, select rational parameters of the elements, and reduce design costs. The paper shows the results of modeling the operation of a virtual test bench with an air suspen-sion in the most typical loading modes, identifying the most dangerous modes. The efficiency and adequacy of the mathematical model of the suspension was proved. Examples of determining the force in all the joints of the structure, the choice of maximum loads for design calculations when designing the air suspension of vehicle were shown.

scholarly journals Assessing the Impact of Regional Budget Expenditures on Average Wages

2020 ◽  
Vol 16 (1) ◽  
pp. 61-69
Author(s):  
Denis M. Zhuravlyov
Keyword(s):  
Mathematical Model ◽  
Economic System ◽  
Labour Market ◽  
Model Performance ◽  
Practical Interest ◽  
Qualitative Assessment ◽  
Average Wage ◽  
Software Application ◽  
Regional Budget ◽  
The Impact

The author discusses the development of an economic-mathematical model for assessing the impact of regional budget expenditures on the average wage for solving the problems of analyzing macroeconomic indicators and forming strategic planning tools for the development of the regional socioeconomic system. The Object of the Study - expenses of the regional budget of the constituent entity of the Rossiyskaya Federatsiya, aimed at developing and maintaining the infrastructure contributing to the provision of comfortable working conditions for citizens. The Subject of the Study - methods of economic and mathematical modelling, processes of formation of the average wage. The Purpose of the Study. Development of an economic and mathematical model for assessing the impact of regional budget expenditures on the average wage level for quantitative and qualitative assessment of the effectiveness of the totality of measures arising in the process of its implementation. The Main Provisions of the Article. The labour market is the basis of a market economy and indicator, the importance of which makes it possible to draw conclusions both about the state of the economy as a whole and about the success of the reforms and transformations, in particular. His condition directly affects the performance indicators of the socio-economic system of the region: productivity, profitability, growth, etc. Research and identification of factors that have a significant impact on the processes of formation and functioning of the labor market is of not only theoretical, but practical interest. The following tasks have been solved: the economic and mathematical models are formalized; the layout of the indices characterizing the object of study; the corresponding mathematical apparatus is selected; software application developed; the proof of model performance is performed. As a methodological apparatus, methods of regression and correlation analysis were used. As a result, an economic-mathematical model of the category «labour market efficiency» was obtained, the functionality of which is sufficient to substantiate causal relationships between indicators that determine the nature of its functioning. Using the obtained results in practice, it is possible to reasonably form a system of priority long-term guidelines for the development of the socio-economic system of the region, drawn up in the form of relevant program documents. The developed software can be used as a module of a decision support system in the formation and development of a strategy for the region’s accelerated development.

A Modular Code for Real Time Dynamic Simulation of Gas Turbines in Simulink

2002 ◽  
Vol 128 (3) ◽  
pp. 506-517 ◽  
Author(s):  
S. M. Camporeale ◽  
B. Fortunato ◽  
M. Mastrovito
Keyword(s):  
Mathematical Model ◽  
Real Time ◽  
Gas Turbine ◽  
Dynamic Behavior ◽  
Gas Turbines ◽  
Simulation Software ◽  
Computational Time ◽  
High Fidelity ◽  
Time Step ◽  
The Mathematical Model

A high-fidelity real-time simulation code based on a lumped, nonlinear representation of gas turbine components is presented. The code is a general-purpose simulation software environment useful for setting up and testing control equipments. The mathematical model and the numerical procedure are specially developed in order to efficiently solve the set of algebraic and ordinary differential equations that describe the dynamic behavior of gas turbine engines. For high-fidelity purposes, the mathematical model takes into account the actual composition of the working gases and the variation of the specific heats with the temperature, including a stage-by-stage model of the air-cooled expansion. The paper presents the model and the adopted solver procedure. The code, developed in Matlab-Simulink using an object-oriented approach, is flexible and can be easily adapted to any kind of plant configuration. Simulation tests of the transients after load rejection have been carried out for a single-shaft heavy-duty gas turbine and a double-shaft aero-derivative industrial engine. Time plots of the main variables that describe the gas turbine dynamic behavior are shown and the results regarding the computational time per time step are discussed.

The Prospects for Lightweight Ship Propulsion Systems

1978 ◽  
Author(s):  
S. C. Kuo ◽  
T. L. O. Horton ◽  
H. T. Shu ◽  
W. R. Seng
Keyword(s):  
Gas Turbines ◽  
Economic Feasibility ◽  
Closed Cycle ◽  
Propulsion Systems ◽  
Ship Propulsion ◽  
Parametric Analyses ◽  
Propulsion Power

A comprehensive systems study was made to evaluate the technological and economic feasibility of utilizing open- and closed-cycle gas turbines for providing advanced lightweight propulsion power for future Navy ship applications. Extensive parametric analyses were made of the performance and weight characteristics for the propulsion engine cycles selected, and applicable turbomachinery technologies were reviewed to estimate their future advances expected. The payload capabilities and endurance limitations resulting from utilization of different propulsion systems in the 40,000 -to 300,000-shp range for selected ship types were identified.

Regenerative Gas Turbines With Divided Expansion

2004 ◽  
Author(s):  
Brian Elmegaard ◽  
Bjo̸rn Qvale
Keyword(s):  
Mathematical Model ◽  
Gas Turbines ◽  
High Efficiency ◽  
Limited Range ◽  
Simulation Program ◽  
Operating Parameters ◽  
Gas Generator ◽  
Extensive Simulation ◽  
Power Turbine ◽  
The Mathematical Model

Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100kW. In order to improve the economics of the plants, ways to improve their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas generator part for recuperation ahead of the expansion in the power turbine. The present study is more complete than the predecessors in that the ranges of the parameters have been extended and the mathematical model is more realistic using an extensive simulation program. It is confirmed that the proposed divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high. The advantages of the divided expansion manifest themselves over a rather limited range of the operating parameters, that lies outside the range required to make modern micro turbines economically competitive.

Design and experimental study of the self-adaptive splitting technology of lotus seeds

2020 ◽  
pp. 1-11
Author(s):  
Ange Lu ◽  
Qiucheng Ma ◽  
Jie Ma
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Firefly Algorithm ◽  
Test Bench ◽  
The Self ◽  
Linkage Mechanism ◽  
Lotus Seed ◽  
Medicinal Value ◽  
Splitting Process ◽  
Self Adaptive

The lotus plumule has high medicinal value and is an important part of the lotus seed. Usually, the lotus seed must be split symmetrically into two halves through a splitting process to obtain an intact lotus plumule. However, this process is difficult to mechanize and automate, as different lotus seeds are of different sizes. In this study, a novel automatic self-adaptive splitting technology (SAST) is proposed for lotus seeds, based on a specially designed combined linkage mechanism and a roller pair centering mechanism. The technology can automatically adjust the position of the splitting point taper punch according to the size of the lotus seed and ensure that the tip of the punch is on the axis of the lotus seed. First, the centering deviation of the centering mechanism was analyzed. A mathematical model for the SAST was developed, and the key parameters were optimized using the firefly algorithm. An automatic splitting machine and a test bench were designed for centering deviation measurements, and both centering and splitting experiments were conducted. The generated maximum centering deviation of the SAST was <0.176 mm; the highest accurate splitting rates of 95% and 93.05% were achieved for unclassified and graded lotus seeds, respectively.

Investigation of the Influence of the Location of the Unified Mass on the Formed Vibrations of a Thin Containing Extended Shell

2019 ◽  
Vol 945 ◽  
pp. 885-892 ◽  
Author(s):  
O.E. Sysoev ◽  
A.Y. Dobryshkin ◽  
Nyein Sit Naing ◽  
A.V. Baenkhaev
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Test Bench ◽  
Cylindrical Shells ◽  
Forced Vibrations ◽  
Cyclic Loads ◽  
Attached Mass ◽  
Mass System ◽  
Thin Walled ◽  
Reduced Scale

The operation of a structure of thin-walled open cylindrical shells with high economic efficiency is associated with the phenomenon of oscillations and resonance from the effects of cyclic loads and systems of attached masses. The oscillation processes of such structures are not sufficiently studied at present. The article describes a test bench for testing open thin-walled cylindrical shells hinged on the edges that carry a system of attached masses, and the results of experiments on the nature of a reduced-scale shell model are presented. The attached mass system represents metal cylinders of different masses arranged in a certain sequence on the shell body. The experimental dependence of the change in the frequency spectrum of the shell oscillations on the number, mass, and location of the system of attached masses is obtained. A mathematical model is developed for the behavior of an open thin-walled cylindrical shell with a system of attached masses, consistent with the experimental data for forced vibrations of the shell.

A modular dynamic mathematical model of thermoelectric elements for marine applications

Energy ◽  
2016 ◽  
Vol 94 ◽  
pp. 13-28 ◽  
Author(s):  
Chariklia A. Georgopoulou ◽  
George G. Dimopoulos ◽  
Nikolaos M.P. Kakalis
Keyword(s):  
Mathematical Model ◽  
Dynamic Mathematical Model ◽  
Marine Applications
Sign in / Sign up

Export Citation Format

Share Document