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In this paper, the effect of mixed convection on the flow behavior and heat transfer around a circular cylinder disclosed to a vertically upward laminar air stream is numerically examine. The buoyancy-aided flow is utilized to eliminate and control the vortex shedding of the cylinder. The influence of the Grashof number, 0 ≤ Gr ≤ 6000, the flow and thermal patterns, as well as the local and mean Nusselt number, is investigated at a constant Reynolds number of 100. The unsteady Navier-Stokes’s equations are solved employing a finite-volume method to simulate numerically the velocity and temperature fields in time and space. The results showed periodic instability in the flow and thermal fields for a range of Grashof number Gr ≤ 1300. Also, there is critical value of Grashof number for stopping this instability and the vortex shedding formed behind the cylinder, by the effect of heating. Thus, by increasing Grashof number between 1400 ≤ Gr ≤ 4000, the periodic flow vanishes and converts into steady flow with twin eddies attached to the cylinder from the back. Furthermore, as Grashof number increases behind Gr ≥ 5000, the flow becomes completely attached to the cylinder surface without any separation.

In this investigation, the tire pyrolysis fuel in (5, 10, 15, 20 vol. percent) has been examined in a single cylinder DI, four-stroke diesel engine with varying EGR rates (10, 20, and 30 percent), at various engine loads and constant speed of 1500 rpm. The study has expanded further in terms of studying the combined impact of EGR and magnetic conditioner effect. The trials have been carried out by utilizing a permanent Neodymium magnet with a field intensity of 8000 Gauss as a Dipole pole, which has been installed on the fuel line before the fuel injector. Because of the strong magnetic field this magnet creates, the hydrocarbons change their direction. As a result, during the combustion phase, the molecule interlocks with the oxygen, resulting in enhanced burning in the diesel engine. The improved combustion results in more combustion and less toxic gas emissions from the engine. The combining impacts of WTOP10 fuel addition +8000Gauss and EGR10 applications have demonstrated that the highest heat release rate and the maximum incylinder pressure have been mainly boosted. While the center of the heat release rates has shifted toward TDC, combustion durations have remained rather constant. Reasonable increases in the BTE and maximum decreases in the BSFC have been observed with WTOP10+8000Gauss10 percent EGR. Despite dramatic decreases in CO emissions, there have been increases at high engine loads. On the other hand, CO2 emissions have been marginally increased at all engine loads. [ABSTRACT FROM AUTHOR]

This study considers the effect of Eichhornia Crassipes Biodiesel (ECB) blends on the performances, combustion, and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode (DFM) and equipped with an Exhaust gas recirculation technique (EGR). In particular, a single-cylinder, fourstroke, water-cooled diesel engine was utilized and four modes of fuel operation were considered: mode I, the engine operated with an ordinary diesel fuel; mode II, the engine operated with the addition of 2.4 L/min of liquefied petroleum gas (LPG) and 20% EGR; mode III, 20% ECB with 2.4 L/min LPG and 20% EGR; mode IV, 40% ECB with 2.4 L/min LPG and 20% EGR. The operation conditions were constant engine speed (1500 rpm), variation of load (25%, 50%, 75%, and 100%), full load, with a compression ratio of 18, and a time injection of 23° BTDC (Before top died center). With regard to engine emissions, carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons (UHC), and nitrogen oxide (NOX) were measured using a gas analyzer. The smoke opacity was measured using an OPABOX smoke meter. By comparing the results related to the different modes with mode I at full load, the BTE (Brake thermal efficiency) increased by 20.17%, 11.45%, and 12.66% with modes II, III, and IV, respectively. In comparison to the results for mode II, the BTE decreased due to the combustion of ECB blends by 7.26% and 6.24% for mode III and mode IV, respectively, at full load. In comparison to mode II, the Brake specific energy consumption (BSEC) increased with the ECB substitution. With ECB blends, there is a noticeable decrease in the CO, CO2, and UHC emissions at a partial load. Furthermore, the 20% ECB has no effect on CO emissions at full load. For modes II and IV, the CO2 increased by 33.33% and 19%, respectively, while the UHC emissions were reduced by 14.49% for mode III and 26.08% for mode IV. The smoke of mode III was lower by 7.21%, but for mode IV, it was higher by 12.37%. In addition, with mode III and mode IV, the NOx emissions increased by 30.50% and 18.80%, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering & Sustainable Development is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Engineering & Sustainable Development is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)