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Single Cylinder (single + cylinder)

Distribution by Scientific Domains

Engineering	60%

Selected Abstracts

Numerical simulation of heat transfer and fluid flow over two rotating circular cylinders at low Reynolds number

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 4 2010
Nikolay Pavlovich Moshkin
Abstract This paper presents a numerical investigation of the characteristics of two-dimensional heat transfer in a steady laminar flow around two rotating circular cylinders in a side-by-side arrangement. The simulation is validated by comparing our computational results for the large gap-spacing between cylinder surfaces with the available numerical and experimental data for a single cylinder. Numerical simulations were carried out for the Reynolds number range 10,Re ,40, for the Prandtl number range 0.7,Pr ,50, and for a variety of absolute rotational speeds (|,|,2.5) at different gap spacings. The study revealed that for the range of parameters considered the rate of heat transfer decreases with the increasing speed of rotation. An increase of the Prandtl number resulted in an increase in the average Nusselt number. The streamlines and isotherms are plotted for a numbers of cases to show the details of the velocity and thermal fields. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20293 [source]

An experimental investigation on manifold-injected hydrogen as a dual fuel for diesel engine system with different injection duration

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2009
N. Saravanan
Abstract Stringent emission norms and rapid depletion of petroleum resources have resulted in a continuous effort to search for alternative fuels. Hydrogen is one of the best alternatives for conventional fuels. Hydrogen has both the benefits and limitation to be used as a fuel in an automotive engine system. In the present investigation, hydrogen was injected into the intake manifold by using a hydrogen gas injector and diesel was introduced in the conventional, mode which also acts as an ignition source for hydrogen combustion. The flow rate of hydrogen was set at 5.5,l,min,1 at all the load conditions. The injection timing was kept constant at top dead center (TDC) and injection duration was adjusted to find the optimized injection condition. Experiments were conducted on a single cylinder, four stroke, water-cooled, direct injection diesel engine coupled to an electrical generator. At 75% load the maximum brake thermal efficiency for hydrogen operation at injection timing of TDC and with injection duration of 30°CA is 25.66% compared with 21.59% for diesel. The oxides of nitrogen (NOX) emission are 21.7,g,kWh,1 for hydrogen compared with diesel of 17.9,g,k,Wh,1. Smoke emissions reduced to 1 Bosch smoke number (BSN) in hydrogen compared with diesel of 2.2 BSN. Hydrogen operation in the dual fuel mode with diesel exhibits a better performance and reduction in emissions compared with diesel in the entire load spectra. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Influence of advanced injection timing on the performance and emissions of CI engine fueled with ethanol-blended diesel fuel

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2008
Cenk Sayin
Abstract Ethanol has been considered as an alternative fuel for diesel engines. On the other hand, injection timing is a major parameter that sensitively affects the engine performance and emissions. Therefore, in this study, the influence of advanced injection timing on the engine performance and exhaust emissions of a single cylinder, naturally aspirated, four stroke, direct injection diesel engine has been experimentally investigated when using ethanol-blended diesel fuel from 0 to 15% with an increment of 5%. The original injection timing of the engine is 27° crank angle (CA) before top dead center (BTDC). The tests were conducted at three different injection timings (27, 30 and 33° CA BTDC) for 30 Nm constant load at 1800 rpm. The experimental results showed that brake-specific energy consumption (BSEC), brake-specific fuel consumption (BSFC), NOx and CO2 emissions increased as brake-thermal efficiency (BTE), smoke, CO and HC emissions decreased with increasing amount of ethanol in the fuel mixture. Comparing the results with those of original injection timing, NOx emissions increased and smoke, HC and CO emissions decreased for all test fuels at the advanced injection timings. For BSEC, BSFC and BTE, advanced injection timings gave negative results for all test conditions. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Geometric parameters of isotropic ensembles of right cylinders from the small-angle-scattering correlation function

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 5 2010
Wilfried Gille
The scattered intensity of ensembles of right homogeneous quasi-diluted cylinders with constant oval right section (RS) and volume fraction , are analyzed using the small-angle-scattering (SAS) correlation function (CF) ,(r) = ,(r, ,) in the isotropic two-phase approximation. A relation between the CF of the cylinder RS, ,0(r), and the CF of the single cylinder of height H, ,0(r, H), allows the calculation of the explicit cylinder parameters of height, surface area, RS surface area, RS perimeter and volume. This is accomplished by evaluating the first two derivatives of ,0(r) at r = 0. Without the assumption of an oval RS, neither H nor the RS surface area can be uniquely determined. [source]

Low-angle scattering by cylindrical structures

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 1 2010
Girija Bhushan Mitra
A theory of diffraction at small angles of scattering by a cylindrically constructed structure has been developed and general expressions for two- and three-dimensional cylindrically curved crystallites have been obtained. Modified expressions have been derived for special cases of (a) a single arc of equiangularly spaced identical atoms, (b) several coaxial arcs each having an equal number of equiangularly spaced identical atoms and (c) such arcs arranged at equal distances along the common axis of the arc, including single cylinders and multilayered cylindrical structures. From the expressions obtained, it is possible to measure the magnitudes of the radius of the cylinder, the length of the cylinder, the angular distance between the scattering atoms on each cylindrical arc, their atomic number and the radius of the hole inside each cylindrical structure when a particular tube is considered for a particular purpose or even when predicting the properties required by a nanotube for a particular purpose. [source]