EFFECTS OF BRAKE DISC GEOMETRICAL PARAMETERS AND CONFIGURATIONS ON AUTOMOTIVE BRAKING THERMAL PERFORMACE

2008 ◽  
Vol 32 (2) ◽  
pp. 313-324 ◽  
Author(s):  
Zhongzhe Chi ◽  
Greg F. Naterer ◽  
Yuping He
Keyword(s):  
Numerical Simulations ◽  
Thermal Performance ◽  
Air Flow ◽  
Aerodynamic Characteristics ◽  
Geometrical Parameters ◽  
Brake Disc ◽  
Disc Brakes ◽  
Parametric Studies ◽  
Flow Through ◽  
Brake Rotors

This paper examines the effects of geometrical parameters of pillar post rotors on the thermal performance of automotive vehicle brakes. The thermal performance of vented disc brakes strongly depends on the aerodynamic characteristics of the air flow through the rotor passages. These air flow passages are determined by the geometrical parameters of the brake rotors. In this study, different pillar post rotor models are considered and the corresponding numerical simulations are performed, in order to investigate the effects of various geometrical parameters on the thermal performance. These geometrical parameters include the shape, size, and distribution of a pillar post. The new insight from these parametric studies provides useful guidelines to optimize the geometry of pillar post rotors of automotive vehicles.

scholarly journals Thermal stress analysis of different full and ventilated disc brakes

2015 ◽  
Author(s):  
C. Baron Saiz ◽  
T. Ingrassia ◽  
V. Nigrelli ◽  
V. Ricotta
Keyword(s):  
Thermal Stress ◽  
Working Conditions ◽  
Brake Disc ◽  
Thermomechanical Behaviour ◽  
Disc Brakes ◽  
High Gradients ◽  
Different Shapes ◽  
Brake Rotors ◽  
Short Time ◽  
Braking Phase

During the braking phase, the heat produced by friction between pads and disc cannot be entirely dissipated. Consequently, the brake disc, especially if very hard braking occur, can accumulate large amounts of heat in a short time so producing high gradients of temperature on it. Under these conditions, functionality and safety of the brake system can be compromised. The object of this study is to investigate, under extreme working conditions, the thermomechanical behaviour of different brake rotors in order to evaluate their efficiency and stability and to identify any compromising weakness on them. In particular, by means of FEM thermo-mechanical coupled analyses, one full disc and three ventilated rotors with different shapes have been studied. A very hard (fading) test has been used to evaluate the performances of the discs in terms of temperature distribution, stresses and strains. Obtained results demonstrate that the analysed ventilated discs, unlike the full rotor, can be effectively used in very hard working conditions, always ensuring high safety levels. Among the studied rotors, the curved-vanes disc was found to be the best solution.

scholarly journals CFD modeling and computation of convective heat coefficient transfer of automotive disc brake rotors -Modelado CFD y cálculo de la transferencia de coeficientes de calor por convección de rotores de freno de disco automotores

2017 ◽  
Vol 2 (29) ◽  
pp. 116
Author(s):  
Ali Belhocine ◽  
Wan Zaidi Wan-Omar
Keyword(s):  
Heat Dissipation ◽  
Air Flow ◽  
Flow Distribution ◽  
Cfd Modeling ◽  
Disc Brake ◽  
Braking System ◽  
Ansys Cfx ◽  
Disc Brakes ◽  
Brake Rotors ◽  
Transient Thermal

Braking system is one of the basic organs to control a car. For many years, the disc brakes have been used in automobiles for safe retardation of the vehicles. During braking, enormous amount of heat will be generated, and for effective braking, sufficient heat dissipation is essential. The specific air flow surrounding the brake rotor depends on the thermal performance of the disc brake and hence, the aerodynamics is an important in the region of brake components. A CFD analysis is carried out on the braking system as the study of this case, to make out the behaviour of air flow distribution around the disc brake components using ANSYS CFX software. The main object of this work is to calculate the heat transfer coefficient (h) of the full and ventilated brake discs as a function of time using the CDF analysis which will be used later in the transient thermal analysis of the disc in ANSYS Workbench 11.0.

Review of the coatings used for brake discs regarding their wear resistance and environmental effect

2021 ◽  
pp. 135065012110706
Author(s):  
Saša Vasiljević ◽  
Jasna Glišović ◽  
Blaža Stojanović ◽  
Aleksandar Vencl
Keyword(s):  
Wear Rate ◽  
Friction Pair ◽  
Wear Intensity ◽  
Brake Disc ◽  
Disc Brakes ◽  
Brake Discs ◽  
Materials Used ◽  
Braking Process ◽  
Brake Rotors ◽  
Deposition Techniques

Wear of a friction pair of brake (brake disc and pads), in addition to reducing the active safety of vehicles, leads to the formation of particles that can affect the environment and human health. In addition to the technologies that are being developed for the collection of particles created by the wear of brakes during braking process, today new materials are being introduced, as well as various technologies for processing friction pairs with the aim of reducing brake wear and thus the formation of particles. Furthermore, today, technologies for coating (cladding) the friction surfaces of disc brakes with some materials are increasingly applied and researched, in order to reduce the wear intensity (wear rate) of disc brakes, i.e. the emission of particles created by wear of friction pairs. The aim of this paper is to analyse and review different deposition techniques and materials used for brake discs coatings, as well as the effect it has on the wear rate of friction pair. There are many coating deposition techniques, and special attention is paid to the technology of laser hardfacing of brake rotors.

scholarly journals Study of a segmented ventilation system of the brake disc and determination of the aerodynamic and heat exchange characteristics of the airflow

2022 ◽  
Vol 25 (6) ◽  
pp. 720-732
Author(s):  
P. A. Polyakov
Keyword(s):  
Boundary Layer ◽  
Heat Exchange ◽  
Work Performance ◽  
Heat Dissipation ◽  
Air Flow ◽  
Ventilation System ◽  
Aerodynamic Characteristics ◽  
Design Parameters ◽  
Brake Disc ◽  
Cfd Modelling

This study aims determine a relationship between the aerodynamic and heat exchange characteristics of the air flow in a segmented ventilation system of the brake disc with improved heat dissipation in the boundary layer of the air flow. Classical equations of heat and mass transfer in the boundary layer of the air flow cooling the brake disc ventilation chamber were used. The cooling performance of the system was assessed using the method of similarity. The obtained theoretical findings were confirmed by CFD-modelling. Mathematical models were developed for vented discs with both continuous grooves and slotted grooves. A criterion for assessing the performance of brake disc ventilation systems was proposed, consisting in turbulization of the air flow inside the device under study. According to the obtained analytical dependencies, a 20-fold acceleration of the air flow decreases the turbulization parameter by 1.24 times. An increase in the temperature difference in the boundary layer by 8 times leads to an increase in the turbulization parame-ter by 86.2 times. Using the criterion proposed for assessing the work performance, the aerodynamic and heat exchange characteristics of the system under study were calculated. As a result, a relationship between the design parameters of the segmented ventilation system and improved heat dissipation in the boundary layer of the cooling air flow is proposed. The conducted CFD modelling confirmed the aerodynamic characteristics of the system under study obtained theoretical-ly. This mathematical model together with the turbulization parameter can be used when both developing modern vented brake discs and assessing the existing cooling systems of friction units in order to minimize the possibility of reduced heat exchange processes.

The Oriented Spray Cooling System for Heat Rejection and Evaporation

2021 ◽  
Author(s):  
Chuck Bowman ◽  
Robert E. Taylor ◽  
Jerry D. Hubble
Keyword(s):  
Thermal Performance ◽  
Cooling System ◽  
Air Flow ◽  
Ambient Air ◽  
Nuclear Regulatory Commission ◽  
Spray Cooling ◽  
Analytical Models ◽  
Water Droplets ◽  
Flow Through ◽  
Regulatory Commission

Abstract Spray ponds offer significant advantages over mechanical draft cooling towers including superior simplicity and operability, lower preferred power requirements, and lower costs. Unlike a conventional spray pond in which spray nozzles are arranged in a flat bed and water is sprayed upward, the Oriented Spray Cooling System (OSCS) is an evolutionary spray pond design in which nozzles are mounted on spray trees arranged in a circle and are tilted at an angle oriented towards the center of the circle. Therefore, each nozzle is exposed to essentially ambient air as water droplets drag air into the spray region while the warm air concentrated in the center of the circle rises. Both of these effects work together to increase air flow through the spray region. Increased air flow reduces the local wet-bulb temperature of the air in the spray pattern, promoting heat transfer and more efficient cooling. The authors have developed analytical models to predict the thermal performance of the OSCS that are based on classical heat and mass transfer and kinetic vector relationships for spherical water droplets that rely only on generic experimental thermal performance data. The model is not limited in application with regard to spray pressure or nozzle spacing or orientation and is not limited by droplet size considerations. The paper compares the predicted performance of the OSCS with full-scale field test results that were measured in compliance with Nuclear Regulatory Commission requirements at the Columbia Generating Station where the ultimate heat sink is two OSCS.

The Oriented Spray Cooling System for Heat Rejection and Evaporation

2019 ◽  
Author(s):  
Charles F. Bowman ◽  
Robert E. Taylor ◽  
Jerry D. Hubble
Keyword(s):  
Thermal Performance ◽  
Cooling System ◽  
Air Flow ◽  
Ambient Air ◽  
Nuclear Regulatory Commission ◽  
Spray Cooling ◽  
Analytical Models ◽  
Water Droplets ◽  
Flow Through ◽  
Regulatory Commission

Abstract Spray ponds offer significant advantages over mechanical draft cooling towers (MDCT) including superior simplicity and operability, lower preferred power requirements, and lower capital and maintenance costs. Unlike a conventional spray pond in which spray nozzles are arranged in a flat bed and water is sprayed upward, the Oriented Spray Cooling System (OSCS) is an evolutionary spray pond design in which nozzles are mounted on spray trees arranged in a circle and are tilted at an angle oriented towards the center of the circle. As a result, each nozzle is exposed to essentially ambient air as water droplets drag air into the spray region while the warm air concentrated in the center of the circle rises. Both of these effects work together to increase air flow through the spray region. Increased air flow reduces the local wet-bulb temperature (LWBT) of the air in the spray pattern, promoting heat transfer and more efficient cooling. The authors have developed analytical models to predict the thermal performance of the OSCS that are based on classical heat and mass transfer and kinetic vector relationships for spherical water droplets that rely only on generic experimental thermal performance data. Therefore, the model is not limited in application with regard to spray pressure or nozzle spacing or orientation and is not limited by droplet size considerations. This paper describes specific details such as nozzle type, orientation, and drop spectrum and details on the analytical model never before published that are used to predict the OSCS performance. The paper compares the predicted performance of the OSCS with the rigorous full-scale field test results that were measured in compliance with Nuclear Regulatory Commission requirements at the Columbia Generating Station (CGS) where the ultimate heat sink (UHS) is two OSCS.

Preliminary Results of Testing a Solar Air Heater Equipped with Turbulators

2017 ◽  
Author(s):  
Miroslaw Zukowski ◽  
Grzegorz Woroniak
Keyword(s):  
Solar Radiation ◽  
Thermal Performance ◽  
Meteorological Data ◽  
Air Flow ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Time Intervals ◽  
Measurement Results ◽  
New Type ◽  
Flow Through

The paper presents the thermal performance of a newly designed device for preheating ventilation air. This new type of a solar air collector is equipped with turbulators to increase heat exchange and eventually to obtain more energy from the Sun. Support elements of this type have not yet been implemented in such heat exchangers. The panel has the following dimensions: width – 0.97 m, length – 1.9 m, thickness – 0.1 m, the area where solar radiation enters the collector – 1.49 m2. Air flow through the exchanger is forced by two radial high flow fans, typically used to cool down servers. The test stand beside the collectors is equipped with an inlet and outlet temperature data recorder and an anemometer to control the air flow rate through the collector. Meteorological data such as solar radiation, wind speed and ambient temperature is obtained from a weather station. The parameters of the working installation have been analysed through the monitoring of measurement variables collected on one-minute time intervals from April to September 2016. The measurement results have been used to determine the thermal performance of the air solar collector of this type. The results of the energy analysis have shown the validity of such an installation.

scholarly journals Design and Analysis of Solid and Cross-Drilled Disc Brake Rotors

10.29007/g49k ◽  
2018 ◽  
Author(s):  
Jimit Vyas ◽  
Mahesh Zinzuvadia ◽  
Mohammedilyas I. Kathadi
Keyword(s):  
Temperature Distribution ◽  
Numerical Analysis ◽  
Thermal Stresses ◽  
Paper Analysis ◽  
Heat Energy ◽  
Brake Disc ◽  
Disc Brake ◽  
Disc Brakes ◽  
Brake Rotor ◽  
Brake Rotors

In this paper analysis of automotive disc brake rotor is carried out with the help of ANSYS 17.1 Academic software. Disc brakes operate on the principle of friction by converting the kinetic energy of the vehicle into heat energy at the contact between disc and pads. The main objective of a disc brake rotor is to store this generated heat energy and dissipate it into the environment as soon as possible. This heat rapidly increases the temperature of the disc at the rubbing surface, resulting in thermal stresses in the components of the brake. Thermal behavior of solid and cross drilled brake disc rotors is studied. For numerical analysis commercially available tool ANSYS is used to determine temperature distribution in the disc.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

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