scholarly journals Empirical Estimation of Ethanol-Methylcellulose based Green Gel Propellant Viscosity at Varying Temperature

2021 ◽  
Vol 23 (07) ◽  
pp. 1293-1302
Author(s):  
Saugata Mandal ◽  
◽  
Balaguru Pandian ◽  
Rajarshi Das ◽  
◽  
...  
Keyword(s):  
Experimental Data ◽  
Power Law ◽  
Empirical Model ◽  
Rheological Behavior ◽  
Empirical Estimation ◽  
Propulsion Systems ◽  
Shear Rates ◽  
Temperature Range ◽  
Shear Thinning Fluids ◽  
Good Agreement

The rheological behavior of the Ethanol based green gels for use in propulsion systems at temperature range of 100C – 500C is investigated by employing a novel empirical model developed. The study is conducted at various shear rates. Empirically predicted results were observed to be in good agreement with experimental data at higher shear rates for both pure and energized gel system (>100 s-1). Considering the results, the present empirical model is deemed suitable for those Non Newtonian shear thinning fluids which obey Power law.

Analysis of Screw-Expander Performance

1989 ◽  
Vol 203 (1) ◽  
pp. 15-20 ◽  
Author(s):  
K C Ng ◽  
T B Lim ◽  
T Y Bong
Keyword(s):  
Experimental Data ◽  
Experimental Work ◽  
Empirical Model ◽  
Saturated Steam ◽  
Polytropic Index ◽  
Work Output ◽  
Predicted Values ◽  
Good Agreement ◽  
Thermodynamic Processes

The paper examines the thermodynamic processes of a helical screw-expander that operates with dry saturated steam at its inlet. The work output of the screw-expander is analysed using a simple ‘pseudo-polytropic’ index. Using the available experimental data from the literature, an empirical model for the prediction of work using the ‘pseudo-polytropic’ indices is formulated. The expansion indices are expressed in terms of built-in volumetric and pressure ratios; how they are formulated is usually given in an expander specification. Based on the empirical model, there is a good agreement between the experimental work and the predicted values.

scholarly journals Determination of Rheological Parameters from Measurements on a Viscometer with Coaxial Cylinders – Choice of the Reference Radius

10.14311/892 ◽  
2006 ◽  
Vol 46 (6) ◽  
Author(s):  
F. Rieger
Keyword(s):  
Experimental Data ◽  
Power Law ◽  
Rheological Behavior ◽  
Experimental Results ◽  
Rheological Parameters ◽  
Concentrated Suspensions ◽  
Rotational Viscometer ◽  
Coaxial Cylinders

Knowledge about rheological behavior is necessary in engineering calculations for equipment used for processing concentrated suspensions and polymers. Power-law and Bingham models are often used for evaluating the experimental data. This paper proposes the reference radius to which experimental results obtained by measurements on a rotational viscometer with coaxial cylinders should be related. 

A Comparison of Rheological Models and Experimental Data of Metallocene Linear Low Density Polyethylene Solutions as a Function of Temperature and Concentration

2016 ◽  
Vol 12 (3) ◽  
pp. 4322-4339
Author(s):  
Salah Hamza
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Low Density Polyethylene ◽  
Effect Of Temperature ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Shear Rates ◽  
Wide Range

Knowledge of rheological properties of polymer and their variation with temperature and concentration have been globally important for processing and fabrication of polymers in order to make useful products. Basheer et al. [1] investigated, experimentally, the changes in rheological properties of metallocene linear low density polyethylene (mLLDPE) solutions by using a rotational rheometer model AR-G2 with parallel plate geometry. Their work covered the temperature range from  to  and  concentration from  to . In this paper, we reconsider Basheer work to describe the rheological behavior of mLLDPE solutions and its dependence on concentration and temperature.Until now, several models have been built to describe the complex behavior of polymer fluids with varying degrees of success. In this article, Oldroyd 4-constant, Giesekus and Power law models were tested for investigating the viscosity of mLLDPE solution as a function of shear rate. Results showed that Giesekus and power law models provide the best prediction of viscosity for a wide range of shear rates at constant temperature and concentration. Therefore, Giesekus and power law models were suitable for all mLLDPE solutions while Oldroyd 4-constant model doesn't.A new proposed correlation for the viscosity of mLLDPE solutions as a function of shear rate, temperature and concentration has been suggested. The effect of temperature and concentration can be adequately described by an Arrhenius-type and exponential function respectively. The proposed correlation form was found to fit the experimental data adequately.

An Alternative Approach for Modeling the Hot Carrier Degradation of the Si/SiO2 Interface

1998 ◽  
Vol 513 ◽  
Author(s):  
Zhi Chen ◽  
Jinju Lee ◽  
Joseph W. Lyding
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Power Law ◽  
Interface Trap ◽  
Hot Carrier ◽  
Alternative Approach ◽  
Physical Insight ◽  
Insight Into ◽  
Good Agreement ◽  
Hot Carrier Degradation

ABSTRACTAn alternative approach for modeling the hot carrier degradation of the Si/SiO2 interface based on the dispersive characteristics of the interface trap generation has been proposed. The timedependent interface trap generation has been modeled using the stretched exponential expression. The conventional power law of degradation is just the approximation of this general form. Very good agreement has been found between the theoretical model and the experimental data. This approach gives more physical insight into the understanding of the mechanism for the interface trap generation.

Empirical estimation of engine-integration noise for high bypass ra-tio turbofan engines

2021 ◽  
Vol 263 (2) ◽  
pp. 4511-4519
Author(s):  
Incheol Lee ◽  
Yingzhe Zhang ◽  
Dakai Lin
Keyword(s):  
Experimental Data ◽  
Pressure Side ◽  
Empirical Estimation ◽  
Low Frequencies ◽  
High Frequencies ◽  
Turbofan Engines ◽  
Proposed Model ◽  
The Impact ◽  
Bypass Ratio ◽  
Good Agreement

To investigate the impact of installation on jet noise from modern high-bypass-ratio turbofan engines, a model-scale noise experiment with a jet propulsion system and a fuselage model in scale was conducted in the anechoic wind tunnel of ONERA, CEPRA 19. Two area ratios (an area of the secondary nozzle over an area of the primary nozzle), 5 and 7, and various airframe configurations such as wing positions relative to the tip of the engine nacelle and flap angles, were considered. Based on the analysis of experimental data, an empirical model for the prediction of engine installation noise was proposed. The model comprises two components: one is the interaction be-tween the jet and the pressure side of the wing, and the other is the interaction between the jet and the flap tip. The interaction between the jet and the pressure side of the wing contributes to the noise at the low frequencies (≤ 1.5 kHz), and the interaction between the jet and the flap tip con-tributes to the noise at the high frequencies. The proposed model showed a good agreement with the experimental data.

scholarly journals Rheological behavior of binary polymer compositions

2019 ◽  
pp. 52-55
Author(s):  
V. I. Korchagin ◽  
L. N. Studenikina ◽  
M. V. Schelkunova
Keyword(s):  
Rheological Behavior ◽  
Partial Replacement ◽  
Capillary Length ◽  
Shear Rates ◽  
Temperature Range ◽  
Binary Polymer ◽  
Waste Production ◽  
Bagley Correction ◽  
Wide Range ◽  
Different Content

The article presents the results of a study of the rheological behavior of binary composites based on serial polyethylene grade LDPE 15803-020 with different content of microcellulose grade Filtracell, in a wide range of temperatures and shear rates during deformation through a capillary diameter of 1 mm and a length of 5 and 30 mm. Stable flow regime is manifested in the temperature range from 160 to 200°C for composites containing microcellulose in an amount of 30 wt.%, and its partial replacement with spent microcellulose (waste production of vegetable oils) can reduce the effective viscosity to 25%, but the upper limit of the temperature range is limited to the exudation of impurities (190°C). The Bagley correction is carried out, the coefficients of the equations describing the dependences of the true shear stress, regardless of the capillary length, are calculated.

Rheological study of orange honey with influence on concentration

2021 ◽  
Vol 37 (4) ◽  
pp. 864-867
Author(s):  
Ioana Stanciu
Keyword(s):  
Rheological Behavior ◽  
High Shear ◽  
Rheological Study ◽  
Shear Rates ◽  
Temperature Range ◽  
High Shear Rates ◽  
Viscosity Sensor

The rheological behavior of orange honey was studied in the temperature range 25-45 degrees Celsius with Haake VT 550 viscometer when the HV1 viscosity sensor at high shear rates 3.3 and 1312s-1. The assortment of orange honey has a dilating behavior being influenced by concentration and humidity. Honey was studied with a humidity of 16%, 17%, 19% and 21%. The rheological behavior is influenced by both humidity and its composition.

scholarly journals Analytical model for electrohydrodynamic thrust

2020 ◽  
Vol 476 (2241) ◽  
pp. 20200220
Author(s):  
Ravi Sankar Vaddi ◽  
Yifei Guan ◽  
Alexander Mamishev ◽  
Igor Novosselov
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Momentum Transfer ◽  
Analytical Model ◽  
First Principles ◽  
Thrust Force ◽  
Propulsion Systems ◽  
One Dimensional ◽  
Charged Species ◽  
Good Agreement

Electrohydrodynamic (EHD) thrust is produced when ionized fluid is accelerated in an electric field due to the momentum transfer between the charged species and neutral molecules. We extend the previously reported analytical model that couples space charge, electric field and momentum transfer to derive thrust force in one-dimensional planar coordinates. The electric current density in the model can be expressed in the form of Mott–Gurney law. After the correction for the drag force, the EHD thrust model yields good agreement with the experimental data from several independent studies. The EHD thrust expression derived from the first principles can be used in the design of propulsion systems and can be readily implemented in the numerical simulations.

THERMAL EXPANSION OF SINGLE CRYSTALS OF ZINC AT LOW TEMPERATURES

1965 ◽  
Vol 43 (7) ◽  
pp. 1328-1333 ◽  
Author(s):  
D. A. Channing ◽  
S. Weintroub
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Single Crystals ◽  
Low Temperatures ◽  
Linear Thermal Expansion ◽  
Optical Interference ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Good Agreement

The linear thermal expansion coefficients αψ of two single crystals of Zn of orientations ψ = 10.8° and 63.9 ° with the hexad axis were measured over the temperature range of about 20–270 °K using an absolute Fizeau optical interference technique. The two principal coefficients, [Formula: see text] and [Formula: see text], corresponding to ψ = 0° and 90 ° respectively, were calculated from the Voigt relation, and their values are compared with previously reported experimental data. Above 60 °K there is good agreement with previous work, and below 60 °K the results confirm, in general, the data obtained by McCammon and White. The Grüneisen parameter γ is essentially constant at about 2.1 in the range 100–270 °K, but below 100 °K γ rises appreciably with decreasing temperature and reaches the value of about 3.5 at 20 °K.

scholarly journals Microplasma microphones

Acta Acustica ◽  
2021 ◽  
Vol 5 ◽  
pp. 37
Author(s):  
Philippe Béquin ◽  
Adalbert Nanda Tonlio ◽  
Stéphane Durand
Keyword(s):  
Experimental Data ◽  
Empirical Model ◽  
Sound Pressure ◽  
Acoustic Pressure ◽  
Electrode Array ◽  
Calibration Method ◽  
Pressure Sensitivity ◽  
Empirical Expression ◽  
Microstructured Electrode ◽  
Good Agreement

It is shown experimentally that a microplasma created by a microstructured electrode array is sensitive to sound pressure. In this paper, two electrode architectures are used to create the microplasma. The sensitivity of these microplasma microphones, close to 0.4 nA/Pa, is estimated using a waveguide and a calibration method by comparison with a reference microphone. An empirical expression of the acoustic pressure sensitivity of microdischarges is proposed. The predictions of this empirical model are in good agreement with the experimental data.

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