Analysis of the combined effect of hydrogrinding process and inclination angle on hydraulic performance of diesel injection nozzles

A computational study to investigate the influence of the orifices inclination and the rounding radius at the orifice inlet (consequence of the hydro-erosive grinding process applied after the orifices machining) over the internal nozzle flow is performed in this paper. The study starts with the analysis of experimental results where the mass flow and momentum flux of two nozzles with very different values of these two variables are compared. This analysis shows relatively small differences in terms of mass flow and momentum flux, since the higher losses associated to the higher deflection of the streamlines with a higher inclination of the orifices are counteracted by the higher rounding radius, which favors the flow entrance to the orifice. To explain this experimental outcome, an extensive computational study involving nine geometries that combine different inclination angles and rounding radius is conducted, in order to quantify the influence of both parameters on the flow separately, as well as to assess the potential of their combination. These geometries are compared in terms of discharge coefficient, critical cavitation conditions and effective injection velocity, among others. Results show differences up to 15% in terms of mass flow rate and 8% for the effective injection velocity among the two extreme cases (lowest inclination and highest hydro-erosion level versus the nozzle with the highest inclination and lowest hydro-erosion level). Given the importance of these phenomena on the subsequent mixing and combustion processes, the results hereby presented are of interest for Diesel engines injectors and combustion chambers designers.This work was partly sponsored by "Ministerio de Economia y Competitividad" in the frame of the project "Comprension de la influencia de combustibles no convencionales en el proceso de inyeccion y combustion tipo diesel", Reference TRA2012-36932. The equipment used in this work has been partially supported by FEDER project funds "Dotacion de infraestructuras cientifico tecnicas para el Centro Integral de Mejora Energetica y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06)", in the frame of the operation program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain. This support is gratefully acknowledged by the authors.Salvador Rubio, FJ.; Carreres Talens, M.; Jaramillo Císcar, D.; Martínez López, J. (2015). Analysis of the combined effect of hydrogrinding process and inclination angle on hydraulic performance of diesel injection nozzles. Energy Conversion and Management. 105:1352-1365. https://doi.org/10.1016/j.enconman.2015.08.035S1352136510

Estimation of a suitable Schmidt number range in diesel sprays at high injection pressure

The aim of this paper is to estimate a suitable range for the Schmidt number value in non-evaporative diesel sprays. For this purpose, mass distribution data obtained from X-ray absorption experiments existing in literature and a theoretical derivation for spray microscopic characteristics have been combined. Firstly, a procedure based on Gaussian concentration profiles has been proposed in order to interpret X-ray absorption results and relate them to physical parameters as local concentration or spray density. After this, information about FWHM (Full Width at Half Maximum) values has allowed to estimate spray angle in the tested conditions by the definition of Gaussian profiles for the mass radial distribution inside the spray. Following, a theoretical model dependent on momentum flux and Schmidt number has been used to simulate local mass concentration evolution along the spray axis and compare it with the values obtained from the experiments. The combination of the experimental and the theoretical data has allowed to estimate a suitable range for the Schmidt number value in such conditions as those existing in diesel sprays. © 2011 Elsevier Masson SAS. All rights reserved.This work was sponsored by "Vicerrectorado de Investigacion, Desarrollo e Innovacion" of the "Universitat Politecnica de Valencia" in the frame of the project "Estudio numeric de la cavitacion en toberas de inyeccion Diesel mediante Grid Computing (Cavigrid) Reference No 2597.Salvador Rubio, FJ.; Ruiz Rosales, S.; Gimeno, J.; De La Morena Borja, J. (2011). Estimation of a suitable Schmidt number range in diesel sprays at high injection pressure. International Journal of Thermal Sciences. 50(9):1790-1798. doi:10.1016/j.ijthermalsci.2011.03.030S1790179850

SYNCHRONIZED FIRING OF DEITERS\u27 NEURONS FOLLOWING CEREBELLAR INHIBITION IN LIDOCAINE TREATED CATS.

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