Application of an Improved Model for the Determination of Acoustic Resonances in Indicator Passages for Combustion Pressure Measurements

2006 ◽  
Author(s):  
Christoph Gosweiller ◽  
Bryan Willson ◽  
Thomas Walter
Keyword(s):  
Experimental Data ◽  
Base Line ◽  
Pressure Measurements ◽  
Pipe Model ◽  
Reference Transducer ◽  
Acoustic Resonances ◽  
Organ Pipe ◽  
Improved Model ◽  
Good Agreement

The acoustic resonances in indicator passages are often modeled using either a Helmholtz or a so called organ pipe acoustical model. However, in practice these models often indicate natural frequencies which are too high. This paper proposes the Bergh and Tijdeman model [1] which is more accurate and which was originally developed for pressure measurements in turbomachinery. This paper presents the theoretical basis for the Berg / Tijdeman model and then uses it to explore signal distortion from a variety of indicator passage geometries. In order to validate the approach, a flush-mounted water-cooled Kistler reference transducer was used to measure accurate in-cylinder combustion data in an automotive Diesel engine. An additional sensor was recess mounted with passages of different geometries. The Bergh Tijdeman model was then applied to investigate the acoustic distortion of the indicator passages. The results show excellent agreement with the experimental data, which are much closer than using the Helmholtz or the organ pipe model. Further the Bergh and Tijdeman model is applied to complex indicator passage geometries with multiple cavities. Again, for comparison, a flush-mounted Kistler reference transducer was used to measure accurate in-cylinder combustion data in a large-bore natural gas engine. Three additional sensors were mounted using different indicator passage geometries. The engine was operated under base line and knocking combustion conditions. The Bergh Tijdeman model was then applied to model the acoustic distortion of the three indicator passages and again showed good agreement with the experimental data. Finally, the paper proposes simple rules for implementing indicator passages in large gas engines.

Numerical evaluation of hydrodynamic characteristics of planing hulls by using a hybrid method

2021 ◽  
pp. 147509022199024
Author(s):  
Emre Kahramanoglu ◽  
Silvia Pennino ◽  
Huseyin Yilmaz
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Design Stage ◽  
Hydrodynamic Characteristics ◽  
Calm Water ◽  
Preliminary Design Stage ◽  
Reduction Function ◽  
Hull Forms ◽  
Good Agreement

The hydrodynamic characteristics of the planing hulls in particular at the planing regime are completely different from the conventional hull forms and the determination of these characteristics is more complicated. In the present study, calm water hydrodynamic characteristics of planing hulls are investigated using a hybrid method. The hybrid method combines the dynamic trim and sinkage from the Zarnick approach with the Savitsky method in order to calculate the total resistance of the planing hull. Since the obtained dynamic trim and sinkage values by using the original Zarnick approach are not in good agreement with experimental data, an improvement is applied to the hybrid method using a reduction function proposed by Garme. The numerical results obtained by the hybrid and improved hybrid method are compared with each other and available experimental data. The results indicate that the improved hybrid method gives better results compared to the hybrid method, especially for the dynamic trim and resistance. Although the results have some discrepancies with experimental data in terms of resistance, trim and sinkage, the improved hybrid method becomes appealing particularly for the preliminary design stage of the planing hulls.

Processing a Brookfield Rotational Viscometer Measurement Results in the MATLAB

2020 ◽  
Vol 834 ◽  
pp. 82-89
Author(s):  
Evgenii Igorevich Kurkin ◽  
Vladislava Olegovna Chertykovtseva ◽  
Yaroslav Vyacheslavovich Zakhvatkin
Keyword(s):  
Experimental Data ◽  
Carbon Fibers ◽  
Power Law Model ◽  
Rotational Viscometer ◽  
Measurement Results ◽  
Automatic Capture ◽  
Type Power ◽  
Short Carbon ◽  
Good Agreement

The Brookfield_to_MATLAB and ViscosityApproximation codes for processing of experiments results for determination of viscosity on a rotational Brookfield DV3T viscometer is developed in the MATLAB. The codes allow to carry out automatic capture data, to calculate the shear rate for standard spindles RV-1 ... RV-7, to sort the measurement results on temperatures, to combine the experimental data and to determine the coefficients of the Andrade type power-law model. Paper describes experiment results on determination of viscosity of the epoxy binder reinforced by short carbon fibers. The coefficients of the viscosity model are determined by the linear regression coefficients. The obtained determination coefficient shows a good agreement of the model with the experimental data. The results are used for study various contents of a mass fraction of fibers: 0%, 5%, 10%, and 15%.

scholarly journals Development of Characterization Techniques of Thermodynamic and Physical Properties Applied to the CO2-DMSO Mixture

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Brice Calvignac ◽  
Elisabeth Rodier ◽  
Jean-Jacques Letourneau ◽  
Jacques Fages
Keyword(s):  
Process Design ◽  
Published Data ◽  
Viscosity Data ◽  
Pressure Measurements ◽  
Co2 Solubility ◽  
Volumetric Expansion ◽  
Characterization Techniques ◽  
Dmso System ◽  
Good Agreement

This work is focused on the development of new characterization techniques of physical and thermodynamic properties. These techniques have been validated using the binary system DMSO-CO2 for which several studies of characterization have been well documented. We focused on the DMSO-rich phase and we carried out measurements of volumetric expansion, density, viscosity and CO2 solubility at 298.15, 308.15 and 313.15 K and pressures up to 9 MPa. The experimental procedures were compared and validated with the available literature data on SC-CO2-DMSO system. We made density and CO2 solubility measurements, using respectively the vibrating tube technology and two static analytical methods. Lastly, we developed an innovative falling body viscosimeter for high pressure measurements. All the measurements made are in good agreement with the already published data in spite of very different experimental techniques. This work is a contribution to the understanding of the DMSO-CO2 binary as it implements new viscosity data. Moreover, it opens new perspectives about the determination of the properties of other systems such as polymers-CO2 and fats-CO2, which are essential for supercritical process design such as extraction, crystallization, chromatography and synthesis reaction.

The use of electron gas modification in the evaluation of the vibration frequencies and the specific heat of lithium

1960 ◽  
Vol 259 (1298) ◽  
pp. 361-369 ◽  
Keyword(s):  
Experimental Data ◽  
Phase Transformation ◽  
Electron Gas ◽  
Vibration Frequencies ◽  
Specific Heats ◽  
Air Temperatures ◽  
Set Up ◽  
Good Agreement ◽  
Secular Determinant

A secular determinant for the determination of vibration frequencies of lithium has been set up by Launay’s method which takes the electron gas into account. Theoretical elastic constants have been used in the calculation of the force constants. Frequencies have been calculated for 47 points of the first Brillouin zone which gives the value of 3 x 1000 = 3000 frequencies by symmetry. Specific heats have been calculated by numerical computation in the range 300 to 6°K and show good agreement with the experimental data. The agreement below liquid-air temperatures is surprising in view of the known phase transformation of lithium.

DIELECTRIC LOSSES IN ISOTENAX N

2003 ◽  
Vol 17 (07) ◽  
pp. 273-279 ◽  
Author(s):  
MIHAI RAZVAN MITROI ◽  
VLADIMIR IANCU ◽  
DOINA ELENA GAVRILA
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Composite Materials ◽  
Frequency Dependence ◽  
Dielectric Losses ◽  
Wagner Model ◽  
Improved Model ◽  
Good Agreement

The limits of the Maxwell–Wagner model for interfacial losses in composite materials are discussed. The model is improved by taking into account the frequency dependence of the loss resistances. The improved model is applied to the statistical analysis of the experimental data obtained on Isotenax N. The results of the model are in very good agreement with the experiment.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

scholarly journals Theory determination of $$\varvec{\bar{B}\rightarrow D^{(*)}\ell ^-\bar{\nu }}$$ form factors at $$\varvec{\mathcal {O}(1/m_c^2)}$$

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Marzia Bordone ◽  
Martin Jung ◽  
Danny van Dyk
Keyword(s):  
Experimental Data ◽  
Light Cone ◽  
Sum Rules ◽  
Form Factors ◽  
Longitudinal Polarization ◽  
Polarization Fraction ◽  
Theoretical Results ◽  
Good Agreement ◽  
Lepton Flavour

Abstract We carry out an analysis of the full set of ten $$\bar{B}\rightarrow D^{(*)}$$B¯→D(∗) form factors within the framework of the Heavy-Quark Expansion (HQE) to order $$\mathcal {O}\left( \alpha _s,\,1/m_b,\,1/m_c^2\right) $$Oαs,1/mb,1/mc2, both with and without the use of experimental data. This becomes possible due to a recent calculation of these form factors at and beyond the maximal physical recoil using QCD light-cone sum rules, in combination with constraints from lattice QCD, QCD three-point sum rules and unitarity. We find good agreement amongst the various theoretical results, as well as between the theoretical results and the kinematical distributions in $$\bar{B}\rightarrow D^{(*)}\lbrace e^-,\mu ^-\rbrace \bar{\nu }$$B¯→D(∗){e-,μ-}ν¯ measurements. The coefficients entering at the $$1/m_c^2$$1/mc2 level are found to be of $$\mathcal {O}(1)$$O(1), indicating convergence of the HQE. The phenomenological implications of our study include an updated exclusive determination of $$|V_{cb}|$$|Vcb| in the HQE, which is compatible with both the exclusive determination using the BGL parametrization and with the inclusive determination. We also revisit predictions for the lepton-flavour universality ratios $$R_{D^{(*)}}$$RD(∗), the $$\tau $$τ polarization observables $$P_\tau ^{D^{(*)}}$$PτD(∗), and the longitudinal polarization fraction $$F_L$$FL. Posterior samples for the HQE parameters are provided as ancillary files, allowing for their use in subsequent studies.

Sound absorption characterization of aluminum foam made by press infiltration casting

2016 ◽  
Vol 12 (4) ◽  
pp. 737-747 ◽  
Author(s):  
J.X. Sun ◽  
C.Y. Duan ◽  
P.S. Liu
Keyword(s):  
Experimental Data ◽  
Absorption Coefficient ◽  
Sound Wave ◽  
Sound Absorption ◽  
Aluminum Foam ◽  
Peak Frequency ◽  
Experimental Result ◽  
Content Type ◽  
Improved Model ◽  
Good Agreement

Purpose The purpose of this paper is to investigate the sound absorption by modeling for the aluminum foam produced by press infiltration casting. Design/methodology/approach First use Johnson-Allard-Champoux (JAC) model to calculate the sound absorption coefficient of the present aluminum foam, and then improve it after finding its deviation from the experimental data, so as to get an improved model that could have a good agreement with the experimental result. Findings Using JAC model to calculate the sound absorption coefficient of the present aluminum foam, it is found that the model may have a good agreement with the experimental data only for the sound wave frequency below the absorption peak frequency, but a large deviation from the experimental result for the sound wave frequency above this frequency. Originality/value Improving JAC model by means of two factors, i.e., the absorption peak frequency and the specific surface area, the resultant improved model could be in good agreement with the experimental data.

scholarly journals Comparison of Hydraulic Conductivity Values Obtained from Empirical Formulae and Laboratory Experiments

2020 ◽  
Vol 68 (4) ◽  
pp. 669-678
Author(s):  
Mario Hala ◽  
Lubomír Petrula ◽  
Zakaraya Alhasan
Keyword(s):  
Experimental Data ◽  
Hydraulic Conductivity ◽  
Laboratory Experiments ◽  
Internal Erosion ◽  
Variable Porosity ◽  
Groundwater Flow Regime ◽  
Series Of Experiments ◽  
Different Grain Size ◽  
Good Agreement

Hydraulic conductivity determination plays an essential role in the investigation of groundwater flow regime which can then influence many field problems such as pumping capabilities in the area, transport of contaminant or heat and soil internal erosion. Numerous equations based on dimensional analysis or experimental measurements have been published since the end of the 19th century for the determination of hydraulic conductivity. However, not all of these formulae are applicable for every material and all of them bring some uncertainty in the value of hydraulic conductivity. This paper contains a description of experimental research carried out concerning the determination of hydraulic conductivity for four types of sand with different grain size distribution curves and variable porosity. Obtained values of hydraulic conductivity ranged from 1 × 10-4 to 4 × 10-3 according to the sample porosity. The series of experiments consisted of 160 separate tests conducted in order to obtain relevant statistical sets. In this paper, the experimental data are discussed and compared with hydraulic conductivities obtained from 6 empirical formulae recommended in a previous study. The comparison showed that some empirical formulae provide a good agreement with the experimental data (the most precise were formulae published by Terzaghi and by Sauerbrey). However, some formulae showed high deviation from measured data (formula published by Zamarin).

Determination of Minimum Fluidization Velocity for Gas-Solid Beds by Experimental Data and Numerical Simulations

2011 ◽  
Author(s):  
Meire Pereira de Souza Braun ◽  
Geraldo Luiz Palma ◽  
Helio Aparecido Navarro ◽  
Paulo Sergio Varoto
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Particle Diameter ◽  
Minimum Fluidization Velocity ◽  
Ergun Equation ◽  
Fluidization Velocity ◽  
Minimum Fluidization ◽  
Experimental Apparatus ◽  
Good Agreement

The purpose of this work is to predict the minimum fluidization velocity Umf in a gas-solid fluidized bed. The study was carried out with an experimental apparatus for sand particles with diameters between 310μm and 590μm, and density of 2,590kg/m3. The experimental results were compared with numerical simulations developed in MFIX (Multiphase Flow with Interphase eXchange) open source code [1], for three different sizes of particles: 310mum, 450μm and 590μm. A homogeneous mixture with the three kinds of particles was also studied. The influence of the particle diameter was presented and discussed. The Ergun equation was also used to describe the minimum fluidization velocity. The experimental data presented a good agreement with Ergun equation and numerical simulations.

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