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Wyszukujesz frazę "friction number" wg kryterium: Temat


Wyświetlanie 1-12 z 12
Tytuł:
Inverse aspects of the three-way catalytic converter operation in the spark ignition engine
Autorzy:
Żmudka, Z.
Postrzednik, S.
Powiązania:
https://bibliotekanauki.pl/articles/242021.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
catalytic converter
conversion rate
flow resistance
local resistance number
friction number
Opis:
There are two sides of the catalyst operation: favourable and adverse. The positive side can be expressed by a conversion rate of harmful substances which is the principal parameter of catalyst work in respect of ecology. However, resistance of exhaust gas flow through the catalytic converter is also an essential problem. This is just the negative, adverse side of the converter operation. The catalytic converter can be treated as a local or linear resistance element of exhaust system. The first model, in which flow resistance generated by a catalyst is treated as local resistance, is more simplified. It is especially useful in case, when detailed constructional data of converter are unknown and the analysis of flow resistances in exhaust system is necessary. The basic measured quantity of flow resistance is pressure drop of exhaust gas within the catalyst. Next, on the basis of taken measurements also resistance number for the tested catalyst is calculated and analysed. Resistance number of the converter is calculated using Darcy model. In the second case, exhaust gas flow resistance through catalyst is treated as linear resistance with energy dissipation (linear frictional resistance) distributed linearly along way of exhaust gas flow. Friction number for the tested converter is calculated and analysed. The problem has been illustrated by the results of experimental researches of the three-way catalytic converter installed in the exhaust system of the spark ignition engine.
Źródło:
Journal of KONES; 2011, 18, 2; 509-516
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of geometric and flow parameters of solar air heater roughened with artificial roughness by Taguchi method
Autorzy:
Sahu, Mukesh Kumar
Mishra, Shivam
Kumar, Avinash
Powiązania:
https://bibliotekanauki.pl/articles/27312207.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
roughness
nusselt number
friction factor
Taguchi method
optimization
Opis:
The paper presents the investigation of the optimum design parameters of a solar air heater (SAH) having wire ribs as artificial roughness by using the Taguchi method. The solar air heater has arc shape roughness geometry with apex upstream flow on the absorber plate. The objective of this paper is to obtain a set of parameters that deliver maximum thermo-hydraulic performance. For this objective, a new parameter the thermo-hydraulic improvement parameter (ηTHIP), has been introduced. For the present analysis, the effects of Reynolds number (Re), relative roughness pitch (P/e), angle of attack (α), and relative roughness height (e/Dh), denoted by A, B, C, and D, respectively, have been considered. An (L18 = 61 · 3 2 ) orthogonal array (OA) was chosen as an experimental plan for applying the Taguchi method. The set of control factors for the solar air heater SAH which delivers the maximum Nusselt number (Nu), and minimum friction factor (fr) – are A6B2C2, and A1B1C3 respectively. To obtain the maximum THIP the experimental set-up requires only one single run using the parameter A6B2C2, hence there is no need to run it all 54 times.
Źródło:
Archives of Thermodynamics; 2023, 44, 3; 3--33
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oscillatory fluid flow and heat transfer through porous medium between parallel plates with inclined magnetic field, radiative heat flux and heat source
Autorzy:
Mehta, T.
Mehta, R.
Mehta, A
Powiązania:
https://bibliotekanauki.pl/articles/265399.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
pole magnetyczne
ciało porowate
promieniowanie
źródło ciepła
oscillatory
inclined magnetic field
porous medium
radiation
heat source
skin-friction coefficient and Nusselt number
Opis:
The aim of the paper is to investigate an oscillatory fluid flow and heat transfer through a porous medium between parallel plates in the presence of an inclined magnetic field, radiative heat flux and heat source. It is assumed that electrical conductivity of the fluid is small and the electromagnetic force produced is very small. The governing coupled equations of motion and energy are solved analytically. Numerical results for the velocity and temperature profiles, local skin friction coefficient and local Nusselt number for various values of physical parameters are discussed numerically and presented graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2020, 25, 2; 88-102
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soret and Dufour effects on MHD free convective flow past a vertical porous plate in the presence of heat generation
Autorzy:
Reddy, G. V. R.
Powiązania:
https://bibliotekanauki.pl/articles/264624.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
promieniowanie
wymiana ciepła
wymiana masy
tarcie
radiation
heat and mass transfer
skin-friction
Nusselt number
Sherwood number
Opis:
An MHD fluid flow is examined over a vertical plate in the presence of Dufour and Soret effects. The resulting momentum, energy and concentration equations are then made similar by introducing the usual similarity transformations. These similar equations are then solved numerically using the Runge-Kutta fourth order method with shooting technique. The effects of various parameters on the dimensionless velocity, temperature and concentration profiles as well as the local values of the skin-friction coefficient, the Nusselt number and Sherwood number are displayed graphically and in a tabular form. A comparison with previously published work is obtained and an excellent agreement is found.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 3; 649-665
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flow features of thermophoretic MHD viscous fluid flow past a converging channel with heat source and chemical reaction
Autorzy:
Kalita, B. K.
Choudhury, R.
Powiązania:
https://bibliotekanauki.pl/articles/2106445.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
magnetohydrodynamika
płyn lepki
termoforeza
liczba Nusselta
MHD
viscous fluid
heat source
thermophoresis
Nusselt number
skin friction
Opis:
A boundary layer flow of an electrically conducting viscous fluid past a converging channel in the presence of thermophoresis, heat source, chemical reaction, viscous dissipation and simultaneous heat and mass transfer characteristics is studied in the paper. An external magnetic field of uniform strength is applied transversely to the channel. The similarity solution has been used to transform the partial differential equations that represent the problem into a boundary value problem of coupled ordinary differential equations, which in turn are solved numerically using MATLAB’s built in solver bvp4c. Numerical computations are carried out to solve the problem and graphical illustrations are made to get the physical insight of the same. The convergent channel flow problem of an incompressible electrically conducting viscous fluid in the presence of a magnetic field has a wide range of applicability in different areas of engineering, specially in industrial metal casting and control of molten metal flow.
Źródło:
International Journal of Applied Mechanics and Engineering; 2021, 26, 3; 72--83
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical dynamic model of coefficient of friction of air pipeline under pressure
Autorzy:
Dmytriv, Vasyl
Dmytriv, Ihor
Horodetskyy, Ivan
Dmytriv, Taras
Powiązania:
https://bibliotekanauki.pl/articles/328390.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
coefficient of friction
Mach number
pressure
aspect ratio
Reynolds number
analytical model
vacuum
współczynnik tarcia
liczba Macha
ciśnienie
współczynnik kształtu
liczba Reynoldsa
model analityczny
próżnia
Opis:
To transport of the air in the pipeline, an analytical model is developed that takes into account the gas velocity, its kinematic and dynamic characteristics - density, viscosity depending on the pressure in a given space of the pipeline. The analytical model makes it possible to calculate the coefficient of friction of gas transportation in the pipeline at intervals of the absolute pressure from 220 to 2 kPa and M < 1 Mach numbers, depending on the diameter and length of the pipeline and physical and technological characteristics of the gas. The K1* aspect ratio is proposed, which characterizes in time the ratio of the dynamic force of movement of gas to the static pressure related to the diameter of the pipeline. The coefficient of air friction was modeled according to the vacuum pressure as a parameter of density and air flow. Air flow was taken from 1.917·10-3 m 3/s to 44.5·10-3 m 3/s respectively, diameters from 0.030 to 0.070 m and Mach number was M = 0.005-0.13. At the vacuum and excess pressures with increasing of Reynolds number and decreasing of Mach number the gas friction coefficient increased linearly. According to the simulation results as the pressure loss and the diameter of the pipeline are increased the friction coefficient increased as well. Analogically, at the vacuum metric pressure when the pressure loss and the diameter of the pipeline are increased the friction coefficient increased. At the pipeline internal diameters of 22, 30, 36 mm accordingly for pressure losses from 2 to 14 kPa the coefficient of air friction varies from 0.006 to 54.527 respectively.
Źródło:
Diagnostyka; 2019, 20, 4; 89-94
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat transfer and friction factor correlation for inclined spherical ball roughened solar air heater
Autorzy:
Murmu, Ramesh
Kumar, Parmanand
Singh, Hari N.
Powiązania:
https://bibliotekanauki.pl/articles/240765.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
renewable energy
spherical ball
relative roughness pitch
relative roughness height
nusselt number
friction factor
angle of attack
Opis:
Flow mechanism under roughened solar air heater is quite complex. This paper is an effort towards determining the governing equations for heat transfer and friction factor for inclined spherical balls roughened ducts. With the availability of these equations, it is easier to predict the thermal and thermohydraulic performance of such roughened solar air heaters. The governing equations are derived based on the experimental data generated under actual outdoor condition at the test rig designed and fabricated at the terrace of the Mechanical Engineering Department, the National Institute of Technology Jamshedpur in India, in terms of roughness and flow parameters. Maximum augmentation in Nusselt number and friction factor for varying relative roughness pitch, relative roughness height, spherical ball height to diameter ratio, and angle of attack was respectively found to be of the order of 2.1 to 3.54 times, 1.87 to 3.21 times, 2.89 to 3.27 times and 1.74 to 3.56 times for Nusselt number and 0.84 to 1.79 times, 1.46 to 1.91 times, 1.67 to 2.34 times and 1.21 to 2.67 times for friction factor in comparison to non-roughened duct. The optimum roughness parameters under present investigation have been found.
Źródło:
Archives of Thermodynamics; 2020, 41, 2; 3-34
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Augmentation in heat transfer and friction of three sides over one side dimple roughened solar duct
Autorzy:
Kumar, Vikash
Powiązania:
https://bibliotekanauki.pl/articles/240256.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dimple roughened
relative roughness pitch
relative roughness height
dimple depth to diameter ratio
nusselt number
friction factor
Opis:
Providing roughness is an effective method to heat fluids to high temperature. Present paper make use of concave dimple roughness on one and three sides of roughened ducts aimed at determining rise in heat transfer and friction of three sides over one side roughened duct. Three sides roughened duct produces high heat transfer compared to one side roughened. Results are shown as a rise in Nusselt number and friction factor of three sides over one side roughened duct. Experimental investigation was conducted under actual outdoor condition at National Institute of Technology Jamshedpur, India to test various sets of roughened collectors. Roughness parameter varied as relative roughness pitch 8–15, relative roughness height 0.018–0.045, dimple depth to diameter ratio 1–2, Reynolds number 2500– 13500 at fixed aspect ratio (width/hight) 8. Highest enhancement in Nusselt number for varying relative roughness pitch, height, and diameter ratio was respectively found as 2.6 to 3.55 times, 1.91 to 3.42 times and 3.09 to 3.94 times compared to one side dimple roughened duct. Highest rise in friction for three sides over one side roughened duct for these varying parameters was respectively found as 1.62 to 2.79 times, 1.52 to 2.34 times and 2.21 to 2.56 times. To visualize the effect of roughness parameter on heat transfer and friction factor, variation in Nusselt number and friction factor for varying roughness parameters with Reynolds number is shown.
Źródło:
Archives of Thermodynamics; 2020, 41, 3; 57-89
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On diffusion of chemically reactive species in a convective flow past an inclined plate with variable surface temperature and variable mass diffusion
Autorzy:
Kirubavathi, J. D.
Palani, G.
Powiązania:
https://bibliotekanauki.pl/articles/266086.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda różnic skończonych
płyta pochylona
tarcie
chemically reactive species
Nusselt number
skin friction
finite-difference methods
inclined plate
Opis:
A numerical solution of a transient natural convection flow past a semi-infinite inclined plate under the combined buoyancy effects of heat and mass transfer along with chemical reaction is presented herewith. The governing boundary layer equations for the above flow problem for a first order homogeneous chemical reaction are set up and non-dimensionalised. An implicit finite difference method is employed to solve the unsteady, nonlinear, integro and coupled partial differential equation. Numerical results are presented for various parameters occurring in the problem. The unsteady velocity, temperature and concentration profiles, local and average skin friction, Nusselt number and Sherwood number are studied for both a generative and destructive reaction.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 905-922
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of turbulent airflow and heat transfer through a rectangular microchannel with different types of baffles
Autorzy:
Saha, Sandip
Raut, Santanu
Das, Apurba Narayan
Powiązania:
https://bibliotekanauki.pl/articles/2141504.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
turbulent air flow
heat transfer
local Nusselt number
friction coefficient
turbulentny przepływ powietrza
wymiana ciepła
liczba Nusselta
współczynnik tarcia
Opis:
The objective of this work is to discuss the turbulent air hydro-thermal phenomena over a rectangular microchannel with different types of baffle (rectangular, triangular, and trapezoidal) mounted on both the walls of the microchannel. The finite volume method with the second order upwind scheme has been utilized to discretize the governing equations and to study the turbulent airflow characteristics; the SST k-ꞷ turbulence model has been adopted. For nine different cases, the different characteristics of fluid flow phenomena and thermal behaviour with the variations in the Reynolds number ranging from [5,000-25,000] and for three different values of inter baffle spacing have been studied in this manuscript. Due to the presence of baffle, it is revealed that the vortex arises on the upper wall and the thermal phenomena enhances with the decrease in inter baffle spacing.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 3; 41-52
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Convective heat transfer in a micropolar fluid over an unsteady stretching surface
Autorzy:
Prasad, K. V.
Vaidya, H.
Vajravelu, K.
Powiązania:
https://bibliotekanauki.pl/articles/266164.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
przepływ niestacjonarny
wymiana ciepła
tarcie
metoda Keller-box
unsteady flow
microrotation
heat transfer
skin friction
Nusselt number
Keller-box method
Opis:
An unsteady boundary layer free convective flow and heat transfer of a viscous incompressible, microploar fluid over a vertical stretching sheet is investigated. The stretching velocity is assumed to vary linearly with the distance along the sheet. Two equal and opposite forces are impulsively applied along the x-axis so that the sheet is stretched, keeping the origin fixed in the micropolar fluid. The transformed highly non-linear boundary layer equations are solved numerically by an implicit finite difference scheme for the transient, state from the initial to the final steady-state. To validate the numerical method, comparisons are made with the available results in the literature for some special cases and the results are found to be in good agreement. The obtained numerical results are analyzed graphically for the velocity, the microrotation, and the temperature distribution; whereas the skin friction, the couple stress coefficient and the Nusselt number are tabulated for different values of the pertinent parameters. Results exhibit a drag reduction and an increase in the surface heat transfer rate in the micropolar fluid flow compared to the Newtonian fluid flow.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 2; 407-422
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Similarity solution for combined free-forced convection past a vertical porous plate in a porous medium with a convective surface boundary condition
Autorzy:
Garg, P.
Purohit, G. N.
Chaudhary, R. C.
Powiązania:
https://bibliotekanauki.pl/articles/265568.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
płyta porowata
tarcie
ośrodek porowaty
konwekcja
combined convection
fixed vertical porous plate
skin-friction coefficient
Nusselt number
convective surface boundary condition
porous medium
Opis:
This paper studies the mathematical implications of the two dimensional viscous steady laminar combined free-forced convective flow of an incompressible fluid over a semi infinite fixed vertical porous plate embedded in a porous medium. It is assumed that the left surface of the plate is heated by convection from a hot fluid which is at a temperature higher than the temperature of the fluid on the right surface of the vertical plate. To achieve numerical consistency for the problem under consideration, the governing non linear partial differential equations are first transformed into a system of ordinary differential equations using a similarity variable and then solved numerically under conditions admitting similarity solutions. The effects of the physical parameters of both the incompressible fluid and the vertical plate on the dimensionless velocity and temperature profiles are studied and analysed and the results are depicted both graphically and in a tabular form. Finally, algebraic expressions and the numerical values are obtained for the local skin-friction coefficient and the local Nusselt number.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 4; 827-836
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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