Effect of flow in the circular 90-degree curved nozzles on ejecting oil jet behavior

IF 0.7 Q4 MECHANICS

Journal of Fluid Science and Technology Pub Date : 2021-01-01 DOI:10.1299/JFST.2021JFST0011

Mikimasa Kawaguchi, G. Nitta, K. Mimura, K. Nishida, Masanobu Koutoku, Ryo Yamamoto, A. Nakashima, Y. Ogata

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引用次数: 1

Abstract

efficiency. Both methods increase the heat Abstract In general, technical methods for improving the thermal efficiency of an engine increase the heat load on peripheral components. Recently, a piston cooling gallery equipped with a flow path has been developed. The engine oil is supplied an oil jet from the nozzle, which is placed under the piston to the piston gallery entrance hall. The nozzle of the oil jet is curved to minimize its size, and the jet interface between ambient air and oil fluctuates near the nozzle exit owing to the shape. Few studies have investigated the behavior of oil jets ejecting from curved pipes. We therefore investigated the flow in two nozzles having a basic bend of 90° with radii of curvature of 15 and 60 mm. Our results clarify the effect of internal flow on the ejecting oil jet behavior. Silicone oil was used as the working fluid. The kinematic viscosity of the silicone oil at 298 K was similar to that of engine oil at 353 K. The behavior of the oil jet was investigated by visualization using background light. A light-emitting-diode displacement meter was installed to measure the jet width. We found that the width of the oil jet increased on the downstream side with large fluctuation of the interface under the condition of a small radius of curvature and large Reynolds number. Furthermore, we time-synchronously measured flow in the nozzle, two-dimensional two-component time-resolved particle image velocimetry, and visualization of the jet. The Reynolds number was set from 1000 to 3000, which is close to that of the engine oil jet. The oil flow velocity in the nozzle fluctuated in the radial direction. The fluctuation became strong under the condition of a small radius and large Reynolds number. The fluctuation propagation speed calculated from the correlation coefficient was as high as the flow speed itself. Furthermore, the jet interface fluctuation speed in the flow direction was as high as the fluctuation propagation speed in the nozzle. Our results demonstrate that the cause of the interface fluctuation is the fluctuation propagation of flow in the nozzle.

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圆形90度弯曲喷嘴内流动对喷射油射流行为的影响

效率。摘要一般来说，提高发动机热效率的技术方法会增加周边部件的热负荷。近年来，研制了一种带有流道的活塞冷却廊。发动机油由喷油嘴供应，喷油嘴位于活塞下方，通往活塞廊入口大厅。油射流的喷嘴为减小其尺寸而弯曲，在喷嘴出口附近，周围空气和油之间的射流界面由于形状而波动。很少有研究对油射流从弯曲管道喷射的行为进行研究。因此，我们研究了两个基本弯曲为90°，曲率半径为15和60毫米的喷嘴中的流动。我们的研究结果阐明了内部流动对喷射油射流行为的影响。工作液采用硅油。硅油在298 K时的运动粘度与发动机油在353 K时的运动粘度相似。利用背景光可视化技术研究了喷油射流的行为。安装了发光二极管位移计来测量射流宽度。研究发现，在曲率半径小、雷诺数大的条件下，油射流的下游宽度增大，界面波动较大。此外，我们对喷嘴内的流量进行了时间同步测量，二维双分量时间分辨粒子图像测速，并对射流进行了可视化。雷诺数设置为1000 ~ 3000，与机油射流的雷诺数接近。喷嘴内的油流速度在径向上有波动。在小半径和大雷诺数条件下，波动变得强烈。由相关系数计算得到的波动传播速度与气流本身的速度相当。射流界面在流动方向上的波动速度与波动在喷嘴内的传播速度相当。结果表明，喷嘴内流动的波动传播是引起界面波动的主要原因。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Fluid Science and Technology MECHANICS-

CiteScore

1.00

自引率

12.50%

发文量

期刊介绍： Journal of Fluid Science and Technology (JFST) is an international journal published by the Fluids Engineering Division in the Japan Society of Mechanical Engineers (JSME). JSME had been publishing Bulletin of the JSME (1958-1986) and JSME International Journal (1987-2006) by the continuous volume numbers. Considering the recent circumstances of the academic journals in the field of mechanical engineering, JSME reorganized the journal editorial system. Namely, JSME discontinued former International Journals and projected new publications from the divisions belonging to JSME. The Fluids Engineering Division acted quickly among all divisions and launched the premiere issue of JFST in January 2006. JFST aims at contributing to the development of fluid engineering by publishing superior papers of the scientific and technological studies in this field. The editorial committee will make all efforts for promoting strictly fair and speedy review for submitted articles. All JFST papers will be available for free at the website of J-STAGE (http://www.i-product.biz/jsme/eng/), which is hosted by Japan Science and Technology Agency (JST). Thus papers can be accessed worldwide by lead scientists and engineers. In addition, authors can express their results variedly by high-quality color drawings and pictures. JFST invites the submission of original papers on wide variety of fields related to fluid mechanics and fluid engineering. The topics to be treated should be corresponding to the following keywords of the Fluids Engineering Division of the JSME. Basic keywords include: turbulent flow; multiphase flow; non-Newtonian fluids; functional fluids; quantum and molecular dynamics; wave; acoustics; vibration; free surface flows; cavitation; fluid machinery; computational fluid dynamics (CFD); experimental fluid dynamics (EFD); Bio-fluid.