Aerodynamic investigations of ventilated brake discs

The heat dissipation and performance of a ventilated brake disc strongly depends on the aerodynamic characteristics of the flow through the rotor passages. The aim of this investigation was to provide an improved understanding of ventilated brake rotor flow phenomena, with a view to improving heat dissipation, as well as providing a measurement data set for validation of computational fluid dynamics methods. The flow fields at the exit of four different brake rotor geometries, rotated in free air, were measured using a five-hole pressure probe and a hot-wire anemometry system. The principal measurements were taken using two-component hot-wire techniques and were used to determine mean and unsteady flow characteristics at the exit of the brake rotors. Using phase-locked data processing, it was possible to reveal the spatial and temporal flow variation within individual rotor passages. The effects of disc geometry and rotational speed on the mean flow, passage turbulence intensity, and mass flow were determined. The rotor exit jet and wake flow were clearly observed as characterized by the passage geometry as well as definite regions of high and low turbulence. The aerodynamic flow characteristics were found to be reasonably independent of rotational speed but highly dependent upon rotor geometry.

Download Full-text

DESIGN AND THERMAL ANALYSIS OF BRAKE ROTOR WITH DIFFERENT MATERIALS

Journal of Manufacturing Engineering ◽

10.37255/jme.v15i2pp44-49 ◽

2020 ◽

Vol 15 (2) ◽

Author(s):

Sugunarani S ◽

Santhosh V

Keyword(s):

Temperature Distribution ◽

Heat Dissipation ◽

Brake Disc ◽

Element Analysis ◽

Analysis Techniques ◽

Engineering Software ◽

The Finite Element Analysis ◽

Brake Rotor ◽

Grey Cast ◽

Aluminium Metal

This work deals with the analysis of heat generation and dissipation in the disc brake of a car during braking and the following release period by using computer-aided engineering software for three different materials of the rotor disc and brake pad. The objective of this work is to analyze the temperature distribution of rotor disc during operation using COMSOL Multiphysics. The work uses the finite element analysis techniques to calculate and predict the temperature distribution on the brake disc and to identify the critical temperature of the brake rotor disc. Conduction, convection and radiation of heat transfer have been analyzed. The results obtained from the analysis indicates that different material on the same retardation of the car during braking shows different temperature distribution. A comparative study was made between grey cast iron (GCI), Aluminium Metal Matrix Composite (AMMC), Alloy steel materials are used for brake disc and the best material for making brake disc based on the rate of heat dissipation have been suggested.

Download Full-text

Numerical investigation of fluid flow and heat transfer characteristics on the aerodynamics of ventilated disc brake rotor using CFD

Thermal Science ◽

10.2298/tsci111219204r ◽

2014 ◽

Vol 18 (2) ◽

pp. 667-675 ◽

Cited By ~ 5

Author(s):

Karuppa Raj ◽

R. Ramsai ◽

J. Mathew ◽

G. Soniya

Keyword(s):

Heat Transfer ◽

Numerical Analysis ◽

Heat Dissipation ◽

Rotational Symmetry ◽

Temperature Drop ◽

Brake Disc ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Ansys Cfx ◽

Brake Rotor

Ventilated brake discs are used in high speed vehicles. The brake disc is an important component in the braking system which is expected to withstand and dissipate the heat generated during the braking event. In the present work, an attempt is made to study the effect of vane-shape on the flow-field and heat transfer characteristics for different configurations of vanes and at different speeds numerically. Three types of rotor configurations circular pillared, modified taper radial and diamond pillar vanes were considered for the numerical analysis. A rotor segment of 20? was considered for the numerical analysis due to its rotational symmetry. The pre processing is carried out with the help of ICEM-CFD and analysis is carried out using ANSYS CFX 12.1. The three dimensional flow through the brake rotor vanes has been simulated by solving the appropriate governing equations viz. conservation of mass, momentum and energy using the commercial CFD tool, ANSYS CFX 12. The predicted results have been validated with the results available in the literature. Circular pillar rotor vanes are found to have more uniform pressure and velocity distribution which results in more uniform temperature drop around the vanes. The effect of number and diameter of vanes in the circular pillared rotor is studied and the geometry is optimized for better mass flow and heat dissipation characteristics.

Download Full-text

Data reduction problems using a 3-hole directional pressure probe to investigate mean flow characteristics in the vaneless gap between impeller and diffuser radial pump

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/52/2/022018 ◽

2013 ◽

Vol 52 (2) ◽

pp. 022018

Author(s):

P Cherdieu ◽

P Dupont ◽

A C Bayeul-Lainé ◽

A Dazin ◽

G Bois

Keyword(s):

Data Reduction ◽

Flow Characteristics ◽

Pressure Probe ◽

Mean Flow ◽

Radial Pump

Download Full-text

Design and analysis of disc brake system in high speed vehicles

International Journal for Simulation and Multidisciplinary Design Optimization ◽

10.1051/smdo/2021019 ◽

2021 ◽

Vol 12 ◽

pp. 19

Author(s):

Anil Babu Seelam ◽

Nabil Ahmed Zakir Hussain ◽

Sachidananda Hassan Krishanmurthy

Keyword(s):

Stainless Steel ◽

Cast Iron ◽

High Speed ◽

Heat Dissipation ◽

Optimal Choice ◽

Grey Cast Iron ◽

Brake Disc ◽

Disc Brake ◽

Brake Rotor ◽

Grey Cast

Brakes are the most important component of any automobile. Brakes provide the ability to reduce or bring automobile to a complete stop. The process of braking is usually achieved by applying pressure to the brake discs. The main objective of this research paper is to propose an appropriate design and to perform analysis of a suitable brake rotor to enhance the performance of the high-speed car. The design of the brake disc is modelled using Solid works and the analysis is carried out using Ansys software. The analysis has been conducted by considering stainless steel and grey cast iron using same brake rotor design so that optimal choice of brake disc can be considered. The analysis considered involves static structural analysis and steady state thermal analysis considering specific parameters on brake rotor to increase the life of brake rotor. From the analysis it is found that the performance and life of disc brake depends upon heat dissipation. From the analysis results it can be concluded that grey cast iron has performed better as compared to stainless steel as this material has anti-fade properties which improves the life of the brake rotor.

Download Full-text

CFD analysis of number of blades on the performance of counter rotating wind turbine designed using blade element momentum theory under transient condition

MATEC Web of Conferences ◽

10.1051/matecconf/201819708015 ◽

2018 ◽

Vol 197 ◽

pp. 08015 ◽

Cited By ~ 1

Author(s):

Didit Setyo Pamuji ◽

Muhammad Agung Bramantya

Keyword(s):

Wind Turbine ◽

Rotational Speed ◽

Flow Characteristics ◽

Wake Flow ◽

Total Power ◽

Transient Condition ◽

Speed Reduction ◽

Blade Element Momentum Theory ◽

Momentum Theory ◽

Blade Element

Unsteady CFD simulations on the effects of number of blades on counter rotating wind turbine (CRWT) were carried out in order to investigate the performance and the flow characteristics. In this paper, 2-bladed and 3-bladed CRWT were designed using Blade Element Momentum Theory (BEMT) which comprised of S833, S834, and S835 airfoils. As a comparison baseline, a SRWT model which have similar design with front rotor of the 3-bladed CRWT would be also investigated. It was found that the SRWT had the same rotational speed with the front rotor of the 3-bladed CRWT. There was about 10.24 % and 11.79 % rotational speed reduction of the rear rotor from the front rotor of 2-bladed CRWTs and 3-bladed CRWTs, respectively. Both of 2-bladed CRWT and 3-bladed CRWT have higher total power than SRWT, thereby generating more larger velocity deficits in the wake flow.

Download Full-text

Wake Flow Patterns Behind Rotating Smooth Spheres and Baseballs

Volume 1: Flow Manipulation and Active Control; Bio-Inspired Fluid Mechanics; Boundary Layer and High-Speed Flows; Fluids Engineering Education; Transport Phenomena in Energy Conversion and Mixing; Turbulent Flows; Vortex Dynamics; DNS/LES and Hybrid RANS/LES Methods; Fluid Structure Interaction; Fluid Dynamics of Wind Energy; Bubble, Droplet, and Aerosol Dynamics ◽

10.1115/fedsm2018-83357 ◽

2018 ◽

Author(s):

Patrick Mortimer ◽

John C. Vaccaro ◽

David M. Rooney

Keyword(s):

Rotational Speed ◽

Reynolds Numbers ◽

Boundary Layer Separation ◽

Wake Flow ◽

Hot Wire ◽

Mean Velocity ◽

Magnus Effect ◽

Power Spectral ◽

The Mean ◽

Smooth Sphere

An experimental investigation into the flow field behind baseballs at two different seam orientations as well as a smooth sphere of the same diameter was undertaken at Reynolds numbers of 5 × 104 and 1 × 105. The rotational speed of the three spheres varied from 0 to 2400 rpm, with data collected in increments of 400 rpm which correspond to relative spin rates between 0 and 0.94. Mean velocity profiles, turbulence in intensity profiles, and power spectral density of the signals were taken using hot-wire anemometry. The smooth sphere wake was seen to change in orientation over a range of relative rotational speeds. The Strouhal number remained constant around 0.24 for relatively low spin rates. The seams on the baseball suppressed any measurable vortex shedding once rotation began, also eliminating any significant change in wake orientation as evidenced by the mean velocity deficit and turbulence intensity profiles. It was concluded that the so-called inverse Magnus effect recorded by previous investigators at a specific Reynolds number / relative rotational speed of a sphere exists only for a smooth sphere and not for a sphere where the boundary layer separation is governed by raised seams.

Download Full-text

Characterization of Vortex Dynamics in the Near Wake of an Oscillating Flexible Foil

Journal of Fluids Engineering ◽

10.1115/1.4033959 ◽

2016 ◽

Vol 138 (10) ◽

Cited By ~ 9

Author(s):

Firas F. Siala ◽

Alexander D. Totpal ◽

James A. Liburdy

Keyword(s):

Large Scale ◽

Flow Characteristics ◽

Leading Edge ◽

Wake Flow ◽

Small Scale ◽

Mean Flow ◽

Near Wake ◽

Trailing Edge ◽

Swirling Strength ◽

The Mean

An experimental study was conducted to explore the effect of surface flexibility at the leading and trailing edges on the near-wake flow dynamics of a sinusoidal heaving foil. Midspan particle image velocimetry (PIV) measurements were taken in a closed-loop wind tunnel at a Reynolds number of 25,000 and at a range of reduced frequencies (k = fc/U) from 0.09 to 0.20. Time-resolved and phase-locked measurements are used to describe the mean flow characteristics and phase-averaged vortex structures and their evolution. Large-eddy scale (LES) decomposition and swirling strength analysis are used to quantify the vortical structures. The results demonstrate that trailing edge flexibility has minimal influence on the mean flow characteristics. The mean velocity deficit for the flexible trailing edge and rigid foils remains constant for all reduced frequencies tested. However, the trailing edge flexibility increases the swirling strength of the small-scale structures, resulting in enhanced cross-stream dispersion. Flexibility at the leading edge is shown to generate a large-scale leading edge vortex (LEV) for k ≥ 0.18. This results in a reduction in the swirling strength due to vortex interactions when compared to the flexible trailing edge and rigid foils. Furthermore, it is shown that the large-scale LEV is responsible for extracting a significant portion of energy from the mean flow, reducing the mean flow momentum in the wake. The kinetic energy loss in the wake is shown to scale with the energy content of the LEV.

Download Full-text

Two- and three-dimensional instabilities in the wake of a circular cylinder near a moving wall

Journal of Fluid Mechanics ◽

10.1017/jfm.2016.810 ◽

2017 ◽

Vol 812 ◽

pp. 435-462 ◽

Cited By ~ 27

Author(s):

Hongyi Jiang ◽

Liang Cheng ◽

Scott Draper ◽

Hongwei An

Keyword(s):

Circular Cylinder ◽

Shear Layer ◽

Three Dimensional ◽

Flow Characteristics ◽

Wake Flow ◽

Mean Flow ◽

Moving Wall ◽

Gap Ratio ◽

Two Factors ◽

Wall Proximity

Two-dimensional (2D) and three-dimensional (3D) instabilities in the wake of a circular cylinder placed near to a moving wall are investigated using direct numerical simulation (DNS). The study covers a parameter space spanning a non-dimensional gap ratio ($G^{\ast }$) between 0.1 to 19.5 and Reynolds number ($Re$) up to 300. Variations in the flow characteristics with $Re$ and $G^{\ast }$ are studied, and their correlations with the hydrodynamic forces on the cylinder are investigated. It is also found that the monotonic increase of the critical $Re$ for 2D instability ($Re_{cr2D}$) with decreasing $G^{\ast }$ is influenced by variations in the mean flow rate around the cylinder, the confinement of the near-wake flow by the plane wall and the characteristics of the shear layer formed above the moving wall directly below the cylinder. The first factor destabilizes the wake flow at a moderate $G^{\ast }$ while the latter two factors stabilize the wake flow with decreasing $G^{\ast }$. In terms of 3D instability, the flow transition sequence of ‘2D steady $\rightarrow$ 3D steady $\rightarrow$ 3D unsteady’ for small gap ratios is analysed at $G^{\ast }=0.2$. It is found that the 3D steady and 3D unsteady flows are triggered by Mode C instability due to wall proximity. However, the Mode C structure is not sustained indefinitely, since interference with the shear layer leads to other 3D steady and unsteady flow structures.

Download Full-text

Broadband liner impedance eduction for multimodal acoustic propagation in the presence of a mean flow

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2016.2.022 ◽

2016 ◽

Vol 11 (2) ◽

pp. 150-155

Author(s):

R. Troian ◽

D. Dragna ◽

C. Bailly ◽

M.-A. Galland

Keyword(s):

Numerical Model ◽

Flow Characteristics ◽

Acoustic Propagation ◽

Rational Fraction ◽

Physical Parameters ◽

Mean Flow ◽

Linearized Euler Equations ◽

Grazing Flow ◽

Propagation Medium ◽

Difference Time

Modeling of acoustic propagation in a duct with absorbing treatment is considered. The surface impedance of the treatment is sought in the form of a rational fraction. The numerical model is based on a resolution of the linearized Euler equations by finite difference time domain for the calculation of the acoustic propagation under a grazing flow. Sensitivity analysis of the considered numerical model is performed. The uncertainty of the physical parameters is taken into account to determine the most influential input parameters. The robustness of the solution vis-a-vis changes of the flow characteristics and the propagation medium is studied.

Download Full-text