scholarly journals Mathematical Model of Proportional Spool Valve with Improved Temperature Dependence

2020 ◽  
pp. 0218-0223
Author(s):  
Petr Chernus ◽  
Valery Sharovatov ◽  
Pavel Chernus
Keyword(s):  
Mathematical Model ◽  
Temperature Dependence ◽  
Spool Valve

Kinetics of autothermal thermophilic aerobic digestion – application and extension of Activated Sludge Model No 1 at thermophilic temperatures

2007 ◽  
Vol 56 (9) ◽  
pp. 137-145 ◽  
Author(s):  
R. Kovács ◽  
P. Miháltz ◽  
Zs. Csikor
Keyword(s):  
Mathematical Model ◽  
Activated Sludge ◽  
Temperature Dependence ◽  
Decay Rates ◽  
Experimental Results ◽  
Aerobic Digestion ◽  
Activated Sludge Model ◽  
Thermophilic Aerobic Digestion ◽  
Autothermal Thermophilic Aerobic Digestion ◽  
Kinetics Of

The application of an ASM1-based mathematical model for the modeling of autothermal thermophilic aerobic digestion is demonstrated. Based on former experimental results the original ASM1 was extended by the activation of facultative thermophiles from the feed sludge and a new component, the thermophilic biomass was introduced. The resulting model was calibrated in the temperature range of 20–60 °C. The temperature dependence of the growth and decay rates in the model is given in terms of the slightly modified Arrhenius and Topiwala-Sinclair equations. The capabilities of the calibrated model in realistic ATAD scenarios are demonstrated with a focus on autothermal properties of ATAD systems at different conditions.

scholarly journals Rheological profiles of blends of the new and used motor oils

2013 ◽  
Vol 61 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Vojtěch Kumbár ◽  
Adam Polcar ◽  
Jiří Čupera
Keyword(s):  
Mathematical Model ◽  
Temperature Dependence ◽  
Dynamic Viscosity ◽  
Rheological Behaviour ◽  
Engine Oil ◽  
Engine Oils ◽  
Used Engine Oil ◽  
And Performance ◽  
Increasing Temperature ◽  
Motor Oils

The objective of this paper is to find changes of a rheological profile of the new engine oil if the used engine oil will be add. And also find changes of a rheological profile of the used engine oil if the new engine oil will be add. For these experiments has been created the blends of the new and the used engine oil. The temperature dependence of the density [kg.m−3] has been measured in the range of −10 °C and +60 °C. The instrument Densito 30PX with the scale for measuring engine oils has been used. The dynamic viscosity [mPa.s] has been measured in the range of −10 °C and +100 °C. The Anton Paar digital viscometer with the concentric cylinders geometry has been used. In the accordance with the expected behaviour, the density and the kinematic viscosity of all oils was decreasing with the increasing temperature. To the physical properties has been the mathematical models created. For the temperature dependence of the density has been used the linearly mathematical model and the exponentially mathematical model. For the temperature dependence of the dynamic viscosity has been used the polynomial 6th degree. The knowledge of density and viscosity behaviour of an engine oil as a function of its temperature is of great importance, especially when considering running efficiency and performance of combustion engines. Proposed models can be used for description and prediction of rheological behaviour of engine oils.

The Temperature Dependence of Band Maxima Molar Absorptivities of the Carbon-Halogen Stretching Mode in Tertiary Butyl Chloride, Bromide, and Iodide in the Liquid Phase

1987 ◽  
Vol 41 (3) ◽  
pp. 468-471 ◽  
Author(s):  
J. E. Katon ◽  
Stanislaus R. Lobo ◽  
J. C. Simpson
Keyword(s):  
Mathematical Model ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Linear Relationship ◽  
Molar Absorptivity ◽  
Absolute Temperature ◽  
Significant Error ◽  
Butyl Chloride ◽  
Tertiary Butyl ◽  
Relationship Of

The absorbances at the peak maxima of the carbon-halogen stretching mode of t-butyl chloride, bromide, and iodide have been measured as a function of temperature. With the use of corrected concentration and pathlengths, these data have been converted into molar absorptivities at the respective peak maxima. The data have then been analyzed statistically for the purpose of developing a mathematical model for the dependency of molar absorptivity, at these peak maxima, on the absolute temperature. In all three cases, a linear relationship of the form e = XT + Y was found to satisfactorily fit the data. The molar absorptivity of all three band maxima decreases approximately 1% per Kelvin. This result indicates that attempts to apply Beer's law at temperatures other than that used to derive the constants will lead to significant error if the temperatures differ by more than a few degrees.

The Temperature Dependence of Band Maxima Molar Absorptivities of the Carbon-Bromine Stretching Modes in n-Butyl Bromide in the Liquid Phase

1987 ◽  
Vol 41 (5) ◽  
pp. 807-809 ◽  
Author(s):  
J. E. Katon ◽  
Stanislaus R. Lobo ◽  
J. C. Simpson
Keyword(s):  
Mathematical Model ◽  
Infrared Spectroscopy ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Energy Difference ◽  
Temperature Dependent ◽  
Butyl Bromide ◽  
Absorption Bands ◽  
A Value

In the determination of energy differences of conformers in the fluid states by infrared spectroscopy it is nearly always assumed that the ratio of the molar absorptivities at the band maxima of two separate absorption bands is independent of temperature. This assumption has been tested by fitting the data obtained from n-butyl bromide to a mathematical model which can be iterated to convergence on a value of the energy difference between the trans and gauche isomers. The data utilized are the C-Br stretching modes of the two conformers at about 655 and 567 cm−1, respectively. It is shown that the assumption of temperature independence of the ratios of the molar absorptivities at the peak maxima is a good one, although both values are individually temperature dependent.

Design and Modelling of a Novel Servovalve Actuated by a Piezoelectric Ring Bender

2015 ◽  
Author(s):  
L. Johan Persson ◽  
Andrew R. Plummer ◽  
Christopher R. Bowen ◽  
Ian Brooks
Keyword(s):  
Mathematical Model ◽  
Closed Loop ◽  
Position Control ◽  
Open Loop ◽  
Closed Loop Control ◽  
Hydraulic Fluid ◽  
Loop Control ◽  
Frequency Responses ◽  
Spool Valve ◽  
The Mathematical Model

This paper describes the design, simulation and testing of a piezoelectric spool valve. An actuator has been connected to the valve and tested under closed loop control. A mathematical model of the valve was produced and a prototype of the valve was tested. The mathematical model is validated against the experimental data. Step and frequency responses for both the valve and actuator are presented. It was found that displacement of the hydraulic fluid by the ring bender had an impact on the valve performance. To reduce the effect of the piezoelectric hysteresis, closed loop spool position control was evaluated. A noticeable difference can be observed between open loop and closed loop performance.

scholarly journals Effect of Modification in Flow Distributor Valve Geometry on the Pressure Drop and Chamber Pressures, in Numerical and Analytical Way, in ORBIT Motor HST Unit

2018 ◽  
Author(s):  
Debanshu Roy ◽  
Amit Kumar ◽  
Rathindranath Maiti ◽  
Prasanta Kumar Das
Keyword(s):  
Mathematical Model ◽  
Pressure Drop ◽  
Cfd Analysis ◽  
Pressure Drops ◽  
Comprehensive Knowledge ◽  
Flow Interactions ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Spool Valve ◽  
Flow Distributor

In this paper, an attempt has been made to analyze the effect of spool port/ groove geometry on the pressure drop and chamber pressures which effect the performance parameters of the flow distributor valve. The work mainly involves formulation of detailed mathematical model of the valve and compare them on the same platform. For mathematical modelling, Matlab has been used. The size of the orifices is considered same throughout the model for better comparison. Initially the construction and functioning of flow distributor valve along with working principles of hydrostatic motor (Rotary Piston) is shown. Next shown the analytical analysis of area change and pressure drops due to different geometry of the spool valve ports. After that the computational fluid dynamics (CFD) analysis has been shown. A complete mathematical model to describe such flow distributor valve is developed after having a comprehensive knowledge of orifice characteristics, flow interactions based on valve geometry. Equations of flow through different orifices (fixed and variable area) of the valve have been developed based on the relationships obtained earlier.

A Mathematical Model to Analyze the Torque Caused by Fluid–Solid Interaction on a Hydraulic Valve

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Emma Frosina ◽  
Adolfo Senatore ◽  
Dario Buono ◽  
Kim A. Stelson
Keyword(s):  
Mathematical Model ◽  
Closed Loop ◽  
Position Control ◽  
Axial Flow ◽  
Closed Loop Control ◽  
Spin Effect ◽  
Loop Control ◽  
Spin Effects ◽  
Study Results ◽  
Spool Valve

In this paper, a three-dimensional (3D) computational fluid dynamics (CFD) methodology to improve the performance of hydraulic components will be shown, highlighting the importance that a study in the fluid mechanics field has for their optimization. As known, the valve internal geometry influences proportional spool valve hydraulic performance, axial flow forces, and spin effects on the spool. Axial flow forces and spin effects interact directly with the position control performance of a direct actuating closed-loop control valve, reducing its capability. The goal of this activity is the study of the torque on the spool induced by the flow and using a CFD 3D methodology to identify causes of this phenomenon and to find a general mathematical solution to minimize the spool spin effect. The baseline configuration and the new ones of the proportional four-way three-position closed-loop control spool valve have been studied with a mathematical model. The models were also validated by the experimental data performed in the Hydraulic Lab of the University of Naples. In particular, the tests allowed to measure the torque on the spool varying the oil flow rate, using a dedicated test bench layout where the spool was directly connected to a torque meter. Several geometries have been analyzed to find the best one to minimize spool spin behavior while maintaining an acceptable pressure drop. The study results confirmed the significant improvement of overall component performance.

DETERMINATION OF THE EMISSIVITY OF STEEL PLATES AND STEEL PLATES WITH A SELECTIVELY ABSORBING COATING BY COOLING CURVES

2019 ◽  
Vol 6 (3) ◽  
pp. 108-111
Author(s):  
Sultan Khamidovich Suleymanov ◽  
Elman Sayad ogli Nabiev ◽  
Valery Grigorevich Dyskin ◽  
Mustafa Umerovich Djanklich ◽  
Oleg Andreevich Dudko ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Temperature Dependence ◽  
Linear Function ◽  
Linear Dependence ◽  
Steel Plates ◽  
Solar Furnace ◽  
Cooling Curves

Analysis of the temperature dependence of the emissivity of materials showed that for many materials the dependence of the emissivity on temperature is a linear function. A mathematical model was created with which the parameters of the linear dependence of the emissivity are determined from the experimental cooling curves. The temperature dependence of the emissivity of steel plates is determined, the systems of a steel plates - selectively absorbing coating and a material of selectively absorbing coating based on NiO - TiO2 obtained on a solar furnace.

Performance Simulation and Analysis of New High-Frequency Valve

2011 ◽  
Vol 219-220 ◽  
pp. 1712-1715
Author(s):  
Yong Zhen Zheng ◽  
Ruan Jian ◽  
Yong He
Keyword(s):  
Mathematical Model ◽  
High Frequency ◽  
Excitation Frequency ◽  
Rotary Motion ◽  
Performance Simulation ◽  
High Frequency Excitation ◽  
Frequency Excitation ◽  
Design Idea ◽  
Spool Valve

This article described the design idea, advantages and operation principle of the new high-frequency valve, designed and analyzed its mathematical model. The rotary motion and axial sliding of valve core are used to realize the independence control of excitation frequency and amplitude. The high-frequency excitation can be achieved by increasing in the number of spool table and selecting the matching relationship between the spool and sleeve valve to improve the spool valve cover window grooves and the communication times per revolution.

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