scholarly journals A Numerical Study of a Compressed Air Engine with Rotating Cylinders

2021 ◽  
Vol 11 (16) ◽  
pp. 7504
Author(s):  
Ján Dižo ◽  
Miroslav Blatnický ◽  
Milan Sága ◽  
Pavol Šťastniak

This article explores the possibility that, during the elimination of conventional combustion engines, the connecting rod becomes deflected. A larger connecting rod angle creates higher lateral pressure on the piston, also leading to greater loads on other engine components. This fact inspired us to develop an applied mechanism design that reduces the disadvantages of conventional combustion engines. The presented mathematical model that describes the designed engine working principle was created utilizing Lagrange’s equations of motion of the second kind and solved in MATLAB. This paper also includes a multibody simulation model of the engine mechanism created using the Simpack software. Based on a comparison of the two methods, the obtained waveforms of the selected kinematic quantities were found to yield minimal deviations. A real prototype was subsequently developed based on the mathematical model outputs. In this manner, we practically verified that the proposed theoretical solution for a non-conventional engine is fully functional.

Author(s):  
Д.А. Тукмаков ◽  
Н.А. Тукмакова

В работе моделируется течение однородного газа и неоднородной среды. Целью работы является изучение влияния размера частиц дисперсной компоненты смеси на истечение дисперсной среды в вакуум и выявление отличий от процесса истечения в вакуум однородного газа. Математическая модель, примененная в данной работе, реализует континуальную методологию моделирования течения неоднородной среды, такого рода методика моделирования движения смеси предполагает решение полной гидродинамической системы уравнений движения для каждой из компонент смеси, системы уравнений движения компонент смеси связаны слагаемыми, отвечающими за межфазное силовое и тепловое взаимодействие. Система уравнений включает уравнения непрерывности для плотности несущей среды и средней плотности дисперсной компоненты смеси. Для описания сохранения импульса несущей среды решалось уравнение Навье-Стокса, для дисперсной компоненты смеси также записывалось уравнение сохранения импульса с учетом слагаемых отвечающих за межкомпонентное взаимодействие. Уравнения сохранения энергии компонент смеси решались с учётом межкомпонентного теплообмена. Система уравнений математической модели дополненная краевыми условиями решалась явным конечно-разностным методом второго порядка точности. В результате моделирования выявлены отличия в распределении параметров сплошной среды при распространении в вакуум чистого газа и газовой взвеси частиц. Также выявлено влияние размера частиц дисперсной фазы на процесс истечение несущей среды и дисперсной компоненты газовзвеси в вакуум. The work simulates the flow of a homogeneous gas and an inhomogeneous medium. The aim of the work is to study the influence of the particle size of the dispersed component of the mixture on the outflow of the dispersed medium into vacuum and to identify differences from the process of outflow of a homogeneous gas into the vacuum. The mathematical model used in this work implements a continuous methodology for modeling the flow of an inhomogeneous medium, this kind of methodology for modeling the mixture motion involves solving the complete hydrodynamic system of equations of motion for each of the components of the mixture, the systems of equations of motion of the components of the mixture are connected by terms responsible for the interphase force and thermal interaction. The system of equations includes continuity equations for the density of the carrier medium and the average density of the dispersed component of the mixture. To describe the momentum conservation of the carrier medium, the Navier-Stokes equation was solved for the dispersed component of the mixture, the equation of momentum conservation was also written taking into account the terms responsible for the intercomponent interaction. The energy conservation equations for the mixture components were solved taking into account inter-component heat transfer. The system of equations of the mathematical model supplemented by boundary conditions was solved by an explicit finite-difference method of the second order of accuracy. As a result of the simulation, differences in the distribution of the parameters of a continuous medium during the propagation of pure gas and gas suspension of particles into a vacuum are revealed. The effect of the particle size of the dispersed phase on the process of the outflow of the carrier medium and the dispersed component of the gas suspension into vacuum was also revealed.


Author(s):  
Yoshifumi Mori ◽  
Takashi Saito ◽  
Yu Mizobe

We focused on vibration characteristics of reciprocating compressors and constructed the mathematical model to calculate the natural frequencies and modes for crank angles and proposed a method to estimate the degree and the suspicious portion of failure by difference of temporal parameter values obtained using measuring data in operation and the mathematical model. In this paper, according to the proposed method, a case study is carried out using the field data, where the data were acquired before and after the failures occurred in the connecting parts of connecting rod, to prospect the difference between each parameter value for two operating states. Inspecting resonant characteristics each in the frequency response data relating to the natural frequencies for bending modes of the piston rod, we determined two resonant frequencies, which could correspond to the 1st and 2nd mode about bending of the piston rod. To equate the calculated each natural frequency from eigen value analysis based on the proposed model with each resonant frequency, we define the error function for the identified problem, namely optimum problem. In the identified results, it is found that some parameter values have much difference and the corresponding failure could occur around the connecting rod. We could show the possibility to detect both the change of the parameter values and the deterioration parts for two different kinds of the operating states by our proposed method.


2012 ◽  
Vol 241-244 ◽  
pp. 988-992
Author(s):  
Cheng Wen Liu

Amorphous alloy material has good soft magnetic properties, so it can be used for stress measurement. At first, the working principle of the stress measurement was analyzed. Secondly its output characteristic mathematical model was established by adopting multivariate linear regression analysis method, and the simulation of the mathematical model was made based on Matlab. Finally a practice measurement with Fe-base TM—M Amorphous alloy was completed. The results of the test have showed that the stress measurement method has some characteristics of being sensitiveness to measure and simple to make a testing system, and a promising method of measuring stress.


Author(s):  
Jia Xiaohong ◽  
Ji Linhong ◽  
Jin Dewen ◽  
Zhang Jichuan

Abstract Clearance is inevitable in the kinematic joints of mechanisms. In this paper the dynamic behavior of a crank-slider mechanism with clearance in its tripod-ball sliding joint is investigated theoretically and experimentally. The mathematical model of this new-type joint is established, and the new concepts of basal system and active system are put forward. Based on the mode-change criterion established in this paper, the consistent equations of motion in full-scale are derived by using Kane method. The experimental rig was set up to measure the effects of the clearance on the dynamic response. Corresponding experimental studies verify the theoretical results satisfactorily. In addition, due to the nonlinear elements in the improved mathematical model of the joint with clearance, the chaotic responses are found in numerical simulation.


2014 ◽  
Vol 945-949 ◽  
pp. 1461-1464
Author(s):  
Han Yu Jin ◽  
Xiu Sheng Cheng ◽  
Xiu Feng Song

The working principle of wet clutch was analyzed and the mathematical model was established for torque deliver. Experimental verification and simulation analysis was carried out for the clutch model in the situation of constant pressure engaging process. An efficiency examination of wet clutch implemented on the test rig and provided theory evidence for pressure precisely control.


2012 ◽  
Vol 490-495 ◽  
pp. 1441-1445 ◽  
Author(s):  
Jian Zhuo Zhang ◽  
Li Zhe Guan ◽  
Kang Kang Li

A kind of hydraulic exciter based on rotary valve control was studied in this paper, the composition of the exciter and its working principle were introduced, and the mathematical model of the system was established. The characters of the system were simulated using MATLAB. From the results of the simulation, we get the relationship of the amplitude of Vibration oil cylinder between the system’s pressure and the exciting frequency. The results can provide theoretical bases to design the hydraulic exciter.


Author(s):  
S-J Seo ◽  
K-Y Kim ◽  
S-H Kang

A numerical study is presented for Reynolds-averaged Navier-Stokes analysis of three-dimensional turbulent flows in a multiblade centrifugal fan. Present work aims at development of a relatively simple analysis method for these complex flows. A mathematical model of impeller forces is obtained from the integral analysis of the flow through the impeller. A finite volume method for discretization of governing equations and a standard k-ɛ model as turbulence closure are employed. For the validation of the mathematical model, the computational results for velocity components, static pressure, and flow angles at the exit of the impeller were compared with experimental data. The comparisons show generally good agreement, especially at higher flow coefficients.


2013 ◽  
Vol 846-847 ◽  
pp. 228-232
Author(s):  
Hua Qing Wang ◽  
Jian Cheng Yang ◽  
Kai Yang ◽  
Jian Feng Qin ◽  
Ze Xu Zhou ◽  
...  

In this paper the working principle of cotton foreign fibers detecting and clearing on line device paving and loosing part is described, and the mathematical model of the relationship between line speed is established, and paving part control system that is suitable for this device has been designed on this basis.


2012 ◽  
Vol 588-589 ◽  
pp. 1458-1461
Author(s):  
Mei Mei Lv ◽  
Tie Liang Lv ◽  
Guo Feng Ou

The system based on the working principle of MAX1978 and TEC, using multi-point at different frequency measurement method, and establishing corresponding mathematical model. Confirmed the pole-zero plot of the PID, according to the amplitude-frequency and phase-frequency characteristics of the mathematical model, and then, adjusted the corresponding resistance and capacitance of the circuit to make the accuracy of the temperature adjustment to 1E-3centigrade.


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