scholarly journals Mathematical Model and Simulator of Rotor With Vibrating Blades Model / Matematyczny I Symulator Stopnia Wirnikowego Z Drgającymi Łopatkami

2014 ◽  
Vol 29 (1) ◽  
pp. 93-102
Author(s):  
Michał Wachłaczenko ◽  
Radosław Przysowa ◽  
Mariusz Żokowski
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Simulation Model ◽  
Rotational Speed ◽  
Operating Conditions ◽  
Bladed Disk ◽  
Input Force ◽  
Turbojet Engine ◽  
Timing Data

Abstract The paper presents description of rotating bladed disk mathematical model. Correctly defined mathematical model of rotor allows creation of numerical simulation model which can be used to generate tip-timing data. First of all, the model is necessary to conduct a research on blade response due to input force in form of changing rotational speed. This enables the possibility to determine turbojet engine terminal operating conditions causing its failure

Examination on Influence Caused by Air Injection Manners Changing in Aerobic-Anaerobic Landfill Method

2015 ◽  
Vol 768 ◽  
pp. 310-317
Author(s):  
Gang Zhen Jiao ◽  
Lei Zhang ◽  
Xiong Shi ◽  
Gui Fu
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Organic Carbon ◽  
Simulation Model ◽  
Solid Phase ◽  
Landfill Gas ◽  
Air Injection ◽  
Carbon And Nitrogen ◽  
Speed Up ◽  
Leachate Quality

In this study, aerobic-anaerobic landfill method (AANM) is focused on as a new way to speed up landfill stabilization, inhibit landfill gas flux, and ameliorate on leachate quality. Numerical simulation model is developed to guide the air injection craftwork and study its effect on achieving above goals. On basis of work finished in last period (0~310 days), air was injected into Lysimeters A (Lys.A) at 0.5 m, and at 2.5 m in Lys.B with the same rate of 1 L/min. In Lys.C there is no air injected. In order to interview the influence by air injection manners changing, from 310 days till 360 days, air injection manners are changed from Mono-site into Double-site in Lys.A and in Lys. B it will be changed from bottom-site (2.5m) into middle-site (1.5m). In Lys.C there will be no changing. By interviewing the comparisons on simulated results in 50 days with and without air injection manners changing, it was found that air injection manners changing in Lys.A causes TOC discharging amount increase more than 6 times, but T-N and GHE resulted from landfill gas decrease 24.1% and 71 % respectively. Air injection manners changing in Lys.B resulted in discharged TOC and T-N increase 108.1 % and 53.5 % respectively, while T-N decreases 3.7 %. On basis of mechanism assumption, mathematical model was developed and according to the simulated results for 5 years, air injected at 2.5 m achieved improvements on stabilization of solid phase organic carbon and nitrogen for 34 % and 13 %, amelioration on leachate quality for 35 % and 62 % of TOC and T-N, and the restraint of GHE for 14 times compared with no air injection case.

scholarly journals Deactivation by sintering of the cobalt catalyst during the Fischer-Tropsch reaction

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Dounia Alihellal ◽  
Lemnouer Chibane ◽  
Mohamed El-Amine Slimani
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Active Sites ◽  
Cobalt Catalyst ◽  
Reaction Rates ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Fischer Tropsch ◽  
Simulation Results ◽  
By Products

In the present work, the deactivation by sintering of cobalt-based catalyst during Fischer-Tropsch synthesis at low temperature was studied by numerical simulation. For this purpose, a mathematical model was developed. The obtained simulation results allowed us to highlight and improve the understanding of the deactivation phenomena of cobalt-based Fischer-Tropsch catalysts by sintering. The main results also show that the sintering phenomenon is strongly dependent on the operating conditions, in particular, the temperature, the pressure, and the H2/CO molar ratio, as well as the reaction by-products such as water. The results obtained can, therefore, be used to understand more the sintering mechanism which may be linked to the change in the concentration of the active sites and the reaction rates.

Numerical and Experimental Study of Shrouded Blade Dynamics Considering Variable Operating Points

2018 ◽  
Author(s):  
Ferhat Kaptan ◽  
Lars Panning-von Scheidt ◽  
Jörg Wallaschek
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Rotational Speed ◽  
Vibration Response ◽  
Operating Conditions ◽  
Test Rig ◽  
Bladed Disk ◽  
Pressure Distributions ◽  
Multiple Contacts ◽  
Operating Points

The optimization of the mechanical design process of turbomachinery has been a subject of research for decades. In this context, many researchers developed efficient numerical methods to calculate the vibration response of bladed disks. In most cases, the studies are restricted to one single operating point of the system, which is sufficient for many applications. For turbomachinery with variable operating points, the conventional computation methods must be extended. Changing the turbine’s rotational speed Ω leads to entirely new load conditions. On the one hand, structural mechanical properties (e.g. stiffening effects) depend on the rotational speed. On the other hand, in case of coupled blades, the pressure distributions in the joints are sensitive to the rotational speed. In this paper, a model of a steam turbine blade is investigated numerically and experimentally. Beside the tip shroud contact, multiple contacts at the root of the blade are considered. The steady-state vibration response is calculated by the well-known harmonic balance method (HBM) and an alternating frequency-time scheme (AFT). In case of variable operating conditions, the stiffness matrix can be described as a matrix polynomial of second order in Ω2. The preload at the joints is based on nonlinear quasistatic finite element analysis and also depends on the rotational speed. For the first time, a computational methodology is presented for the calculation of the forced response of a fully bladed disk with multiple contacts considering rotational speed dependent structural mechanical properties and, in particular, contact pressures. The experimental study is conducted in two steps. Firstly, a single blade model is investigated at non-rotating test conditions. Here, the blade is clamped with two dummies at the shroud. The vibration response is measured for various pressure distributions at the shroud contact. The comparison with simulation results shows a very good agreement. The second step of the experimental study will be the future investigation of a bladed disk assembly on a rotating test rig. An overview of the test rig including operation conditions, excitation methods and measurement techniques is given at the end of the paper.

A Numerical Approach to the Calculation of the Surface Temperature Distribution of Worm Gears

2017 ◽  
Author(s):  
Philipp Roth ◽  
Werner Sigmund ◽  
Sebastian Born ◽  
Daniel Kadach ◽  
Karsten Stahl
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Simulation Model ◽  
Load Capacity ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Surface Temperature Distribution ◽  
Worm Gears ◽  
Over Time

This paper presents a numerical approach to calculate the distribution of the surface temperature of worm gears, which is needed to determine the scuffing load capacity. The simulation model used for the heat transport as well as its boundary conditions are explained. Exemplary results for various operating conditions and temperature courses over time are presented. A comparison of the simulation model with another model from literature reveals deviating results. It is shown that the deviations can be attributed to limitations of the model from literature. These limitations do not apply to the numerical simulation model that is presented in this paper.

Fundamental Examination of Numerical Simulation Model for Pressure Rise due to Underwater Arc

2014 ◽  
Vol 134 (7) ◽  
pp. 604-613 ◽  
Author(s):  
Toshiya Ohtaka ◽  
Tomo Tadokoro ◽  
Masashi Kotari ◽  
Tadashi Amakawa
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Pressure Rise

Evaluation of an improvement in runoff control by means of a construction of an infiltration sewer pipe under a porous asphalt pavement

1997 ◽  
Vol 36 (8-9) ◽  
pp. 397-402
Author(s):  
Yasuhiko Wada ◽  
Hiroyuki Miura ◽  
Rituo Tada ◽  
Yasuo Kodaka
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Asphalt Pavement ◽  
Considerable Effect ◽  
Rainfall Infiltration ◽  
Sewer Pipe ◽  
Porous Asphalt ◽  
Runoff Control

We examined the possibility of improved runoff control in a porous asphalt pavement by installing beneath it an infiltration pipe with a numerical simulation model that can simulate rainfall infiltration and runoff at the porous asphalt pavement. From the results of simulations about runoff and infiltration at the porous asphalt pavement, it became clear that putting a pipe under the porous asphalt pavement had considerable effect, especially during the latter part of the rainfall.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

Numerical Simulation on Mold Electromagnetic Eccentric Stirring and Central Segregation of Round Bloom

2013 ◽  
Vol 652-654 ◽  
pp. 2450-2454
Author(s):  
Zhi Hong Zhang ◽  
Guo Guang Cheng
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Electromagnetic Stirring ◽  
Center Line ◽  
Central Segregation

The paper describes multi-section round bloom casting using external MEMS, equipped with max section D600mm and min D280mm mold, the center line of D280mm mold not coincident with the axis of stirrer coils. it is exist eccentric electromagnetic stirring of mold which section less than max D600mm, a mathematical model of MEMS has been established, the index of central segregation of D280mm macrostructure had decreased less than 1.12 by optimized parameters of electromagnetic stirring and SEN immerse depth, in the end, the quality of round bloom had improved.

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