Search

Your search keyword '"*VELOCITY"' showing total 2 results
2 results on '"*VELOCITY"'

1. Experimental determination of the tire-road friction coefficient for a vehicle with anti-lock braking system.

Author

Uzunov, Hristo, Dimitrov, Kaloyan, and Dechkova, Silvia

Subjects
*ANTILOCK brake systems in automobiles, *FRICTION velocity, *FRICTION, *CENTER of mass, *NUMERICAL analysis, *BRAKE systems
Abstract

In the present study, technical analysis of an experimental research has been carried out to verify tire-road friction coefficient of a vehicle with an anti-lock braking system (ABS) in the process of maximum braking force and in different types of surfaces. The study was conducted using three independent methods, including effective braking distance reading, deceleration measurement with an accelerometer, and a numerical experiment to study vehicle deceleration. The obtained polynomial determined the dependence of the coefficient of friction as a function of the velocity of the center of mass. Verification of experimental results from the first and second experiment was carried out by numerical analysis on the vehicle's deceleration implementing mechanical-mathematical model with ABS module. The results obtained from both the conducted experiment and numerical analysis on tire-road friction coefficient were processed by the methods and means for statistical analysis and expert assessments to determine the extent of results validity and credibility of the performed experiments. Considering the conducted dynamic study on the vehicle braking performance with an anti-lock braking system and the displayed graphic dependences, it has been proved that the maximum braking delay is achieved at constant pressure on the brake pedal. The coefficient of friction decreases with the increase of initial speed for different types of surfaces. High coefficient of friction is explained by the fact that the wheels of the car roll on the highest available slip and the coefficient of friction is similar to that at rest. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

2. Friction pressure drop model of gas-liquid two-phase flow in an inclined pipe with high gas and liquid velocities.

Author

Liu, Zilong, Liao, Ruiquan, Luo, Wei, Ribeiro, Joseph X. F., and Su, Yubin

Subjects
*NATURAL gas pipelines, *FRICTION, *FRICTION velocity, *MULTIPHASE flow, *PIPE, *PRESSURE drop (Fluid dynamics), *PIPE flow, *TWO-phase flow
Abstract

The calculations of friction pressure drop is the most complicated in multiphase flow. Understanding of the friction pressure drop in pipes are of great importance for many industry problems. The existing friction pressure drop models are generally based on low gas and liquid velocities in horizontal and vertical pipes. In this paper, a two-phase flow experiment in inclined pipe was performed. We report the effect of superficial gas and liquid velocities on friction pressure drop, the results indicate that the pressure drop increases with the increase in superficial gas velocity and superficial liquid velocity. According to the experimental analysis and assuming that the fluid in contact with the pipe wall at high velocity is in a liquid phase, we developed a new friction pressure drop model of different flow pattern. This model based on the correlation between the fraction factor and the superficial gas and superficial liquid Reynold numbers. Compared with the previous models, the predictive performance of the present model is good and remains basically stable. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results