SIMULASI NUMERIK PENGARUH VELOCITY STACK PADA MESIN DIESEL YANMAR TERHADAP DISTRIBUSI KECEPATAN DAN TEKANAN ALIRAN FLUIDA

Abstract

Indonesia is suffering from fuel shortages and air pollution. One of them addresses the problem by holding the Energy-Efficient Car Contest (KMHE) which is a race that focuses on energy-efficient vehicles, energy-saving reviews of the way they drive, engine conditions, trajectory geometry, and vehicle aerodynamics. The objective of this study was to analyze the influence of velocity stack variations in radius 0 mm, 30 mm, 50 mm with lengths of 75 mm, 95 mm, 120 mm on the variation of Reynolds numbers 6,17 x 10⁴; 6,86 x 10⁴, 8,23 x 10⁴ on the distribution of fluid flow velocity and pressure, such as visual data of velocity contours, pressure contours and pathlines. The diesel engines operate with a compression-ignition system. The air will be compressed to high pressure and temperature, combustion occurs when fuel is injected. To improve engine performance, modifications are needed on the intake manifold, the velocity stack or bell-mouth. The device is shaped like a trumpet to direct the air flow that enters the combustion chamber and reduce turbulence at the inlets of the manifold so that the flow of air into the combusting chamber is more optimal. This research uses the Computational Fluid Dynamic (CFD) method with Ansys software. Variate the radius of velocity stacks 0 mm, 30 mm, 50 mm with lengths 75 mm, 95 mm and 120 mm. The best result variation of the velocity Stack in the radius 50 mm to length 75 mm at Re 8.23 x 10⁴ with the outlet velocity value 43,494 m/s; the turbulence intensity value 173,429 %; and the entrance length value 18.68 mm.

Keywords: kmhe, diesel engine, intake manifold, velocity stack, computational fluid dynamic