scholarly journals Numerical Study of Heat Transfer and Speed Air Flow on Performance of an Auto-Ventilated Disc Brake

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 160
Author(s):  
R. A. García-León ◽  
N. Afanador-García ◽  
J. A. Gómez-Camperos
Keyword(s):  
Heat Transfer ◽  
Working Conditions ◽  
Heat Dissipation ◽  
Numerical Study ◽  
Operating Conditions ◽  
Simple Type ◽  
Disc Brake ◽  
Ansys Software ◽  
Braking System ◽  
Disc Brakes

In the braking system, the heat dissipation generated by the friction between the disc and pad should be evacuated as quickly as possible. In this work, five common different automotive disc brakes were studied through mathematical theories of heat transfer and numerical methods using the ANSYS software. In addition, a direct comparison between experimental, theoretical, and simulation values found in the open literature was performed to propose a disc brake with an improved geometry in terms of dissipation of heat transfer. The numerical results were considered to propose two possible solutions of disc brake geometries using N-38 ventilation blades used in aeronautic engineering. An improvement in temperature dissipation was achieved by approximately 23.8% compared to the five geometries analyzed with a simple type N-38 ventilation blade. The heat dissipation in the brakes strongly depends on the geometry of the disc, the geometry of the blades, the material from which it is manufactured, the material of the pad, the weight of the vehicle, and the operating conditions, as can be verified with mathematical calculations and experiments. The results obtained demonstrate that the discs can be used effectively in extreme working conditions (80 km/h and 33°C), without affecting the safety of the occupants and the braking system.

Design and Heat Transfer Analysis of Automotive Disc Brakes

2003 ◽  
Author(s):  
J. Jancirani ◽  
S. Chandrasekaran ◽  
P. Tamilporai
Keyword(s):  
Heat Transfer ◽  
Thermal Loading ◽  
Operating Conditions ◽  
Heat Transfer Analysis ◽  
Disc Brake ◽  
Braking System ◽  
Wide Range ◽  
Disc Brakes ◽  
Construction Operation ◽  
Drum Brakes

In the recent scenario of braking system for automobiles, disc brake takes up a wide range of applications, because of its simplicity in construction, operation and not self energizing as in the case of drum brakes. Since the disc brakes takes up a wide range of application, it is essential to ensure the reliable function of the braking system under varied operating conditions. The reliable function of the disc brake system is purely depends on the system based design. In this work, a linear regression technique is used for the optimal design of the disc brake rotor for varied operating conditions. Various forces involved during braking, energy generated during braking and the corresponding effective stopping distances were also calculated using appropriate governing relations and equations. In the varied operating conditions, the heat energy generated during braking should be driven away form the working surfaces of the components. To analyze this thermal loading and cooling phenomenon, a conventional convective heat transfer approach was also formulated and developed in this work. The analytical findings of the above approaches are demonstrated at the end and it is found to be quite satisfactory.

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.

scholarly journals Pool Boiling of Nanofluids on Biphilic Surfaces: An Experimental and Numerical Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Eduardo Freitas ◽  
Pedro Pontes ◽  
Ricardo Cautela ◽  
Vaibhav Bahadur ◽  
João Miranda ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Model ◽  
Heat Dissipation ◽  
Numerical Study ◽  
Pool Boiling ◽  
Temperature Drop ◽  
Surface Cooling ◽  
Average Temperature ◽  
Gold Silver

This study addresses the combination of customized surface modification with the use of nanofluids, to infer on its potential to enhance pool-boiling heat transfer. Hydrophilic surfaces patterned with superhydrophobic regions were developed and used as surface interfaces with different nanofluids (water with gold, silver, aluminum and alumina nanoparticles), in order to evaluate the effect of the nature and concentration of the nanoparticles in bubble dynamics and consequently in heat transfer processes. The main qualitative and quantitative analysis was based on extensive post-processing of synchronized high-speed and thermographic images. To study the nucleation of a single bubble in pool boiling condition, a numerical model was also implemented. The results show an evident benefit of using biphilic patterns with well-established distances between the superhydrophobic regions. This can be observed in the resulting plot of the dissipated heat flux for a biphilic pattern with seven superhydrophobic spots, δ = 1/d and an imposed heat flux of 2132 w/m2. In this case, the dissipated heat flux is almost constant (except in the instant t* ≈ 0.9 when it reaches a peak of 2400 W/m2), whilst when using only a single superhydrophobic spot, where the heat flux dissipation reaches the maximum shortly after the detachment of the bubble, dropping continuously until a new necking phase starts. The biphilic patterns also allow a controlled bubble coalescence, which promotes fluid convection at the hydrophilic spacing between the superhydrophobic regions, which clearly contributes to cool down the surface. This effect is noticeable in the case of employing the Ag 1 wt% nanofluid, with an imposed heat flux of 2132 W/m2, where the coalescence of the drops promotes a surface cooling, identified by a temperature drop of 0.7 °C in the hydrophilic areas. Those areas have an average temperature of 101.8 °C, whilst the average temperature of the superhydrophobic spots at coalescence time is of 102.9 °C. For low concentrations as the ones used in this work, the effect of the nanofluids was observed to play a minor role. This can be observed on the slight discrepancy of the heat dissipation decay that occurred in the necking stage of the bubbles for nanofluids with the same kind of nanoparticles and different concentration. For the Au 0.1 wt% nanofluid, a heat dissipation decay of 350 W/m2 was reported, whilst for the Au 0.5 wt% nanofluid, the same decay was only of 280 W/m2. The results of the numerical model concerning velocity fields indicated a sudden acceleration at the bubble detachment, as can be qualitatively analyzed in the thermographic images obtained in this work. Additionally, the temperature fields of the analyzed region present the same tendency as the experimental results.

CFD Modeling and Simulation of Aeorodynamic Cooling of Automotive Brake Rotor

2018 ◽  
Vol 09 (01) ◽  
pp. 1750008 ◽  
Author(s):  
Ali Belhocien ◽  
Wan Zaidi Wan Omar
Keyword(s):  
Heat Dissipation ◽  
Surface Film ◽  
Transient State ◽  
Cfd Modeling ◽  
Disc Brake ◽  
Cfd Analysis ◽  
Braking System ◽  
Airflow Distribution ◽  
Ansys Cfx ◽  
Brake Rotor

Braking system is one of the important control systems of an automotive. For many years, the disc brakes have been used in automobiles for the safe retarding of the vehicles. During the braking enormous amount of heat will be generated and for effective braking sufficient heat dissipation is essential. The thermal performance of disc brake depends upon the characteristics of the airflow around the brake rotor and hence the aerodynamics is an important in the region of brake components. A CFD analysis is carried out on the braking system as a case study to make out the behavior of airflow distribution around the disc brake components using ANSYS CFX software. We are interested in the determination of the heat transfer coefficient (HTC) on each surface of a ventilated disc rotor varying with time in a transient state using CFD analysis, and then imported the surface film condition data into a corresponding FEM model for disc temperature analysis.

Numerical Simulation of Gas Flow and Heat Transfer in Cross-Wavy Primary Surface Channel for Microtubine Recuperators

2005 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang ◽  
L. Q. Luo ◽  
Z. P. Feng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Numerical Study ◽  
High Reliability ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
The Cross

Three-dimensional numerical simulation was conducted to investigate the flow field and heat transfer performance of the Cross-Wavy Primary Surface (CWPS) recuperators for microturbines. Using high-effective compact recuperators to achieve high thermal efficiency is one of the key techniques in the development of microturbine in recent years. Recuperators need to have minimum volume and weight, high reliability and durability. Most important of all, they need to have high thermal-effectiveness and low pressure-losses so that the gas turbine system can achieve high thermal performances. These requirements have attracted some research efforts in designing and implementing low-cost and compact recuperators for gas turbine engines recently. One of the promising techniques to achieve this goal is the so-called primary surface channels with small hydraulic dimensions. In this paper, we conducted a three-dimensional numerical study of flow and heat transfer for the Cross-Wavy Primary Surface (CWPS) channels with two different geometries. In the CWPS configurations the secondary flow is created by means of curved and interrupted surfaces, which may disturb the thermal boundary layers and thus improve the thermal performances of the channels. To facilitate comparison, we chose the identical hydraulic diameters for the above four CWPS channels. Since our experiments on real recuperators showed that the Reynolds number ranges from 150 to 500 under the operating conditions, we implemented all the simulations under laminar flow situations. By analyzing the correlations of Nusselt numbers and friction factors vs. Reynolds numbers of the four CWPS channels, we found that the CWPS channels have superior and comprehensive thermal performance with high compactness, i.e., high heat transfer area to volume ratio, indicating excellent commercialized application in the compact recuperators.

Analysis of automotive disc brake cooling characteristics

2003 ◽  
Vol 217 (8) ◽  
pp. 657-666 ◽  
Author(s):  
G P Voller ◽  
M Tirovic ◽  
R Morris ◽  
P Gibbens
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Thermal Contact ◽  
Thermal Power ◽  
Disc Brake ◽  
Transfer Coefficients ◽  
Fe Modelling ◽  
Heat Transfer Coefficients ◽  
Brake Application ◽  
Cfd Analyses

The aim of this investigation was to study automotive disc brake cooling characteristics experimentally using a specially developed spin rig and numerically using finite element (FE) and computational fluid dynamics (CFD) methods. All three modes of heat transfer (conduction, convection and radiation) have been analysed along with the design features of the brake assembly and their interfaces. The spin rig proved to be very valuable equipment; experiments enabled the determination of the thermal contact resistance between the disc and wheel carrier. The analyses demonstrated the sensitivity of this mode of heat transfer to clamping pressure. For convective cooling, heat transfer coefficients were measured and very similar results were obtained from spin rig experiments and CFD analyses. The nature of radiative heat dissipation implies substantial e ects at high temperatures. The results indicate substantial change of emissivity throughout the brake application. The influence of brake cooling parameters on the disc temperature has been investigated by FE modelling of a long drag brake application. The thermal power dissipated during the drag brake application has been analysed to reveal the contribution of each mode of heat transfer.

Natural Convection in an Enclosure With Blend of Micro Encapsulated Phase Change Materials

2013 ◽  
Author(s):  
Yasmin Khakpour ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Heat Transfer ◽  
Thermal Expansion ◽  
Natural Convection ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Numerical Study ◽  
Pure Water ◽  
Operating Conditions ◽  
Effective Density

This numerical study investigates the effect of using a blend of micro-encapsulated phase change materials (MEPCMs) on the heat transfer characteristics of a liquid in a rectangular enclosure driven by natural convection. A comparison has been made between the cases of using single component MEPCM slurry and a blend of two-component MEPCM slurry. The natural convection is generated by the temperature difference between two vertical walls of the enclosure maintained at constant temperatures. Each of the two phase change materials store latent heat at a specific range of temperatures. During phase change of the PCM, the effective density of the slurry varies. This results in thermal expansion and hence a buoyancy driven flow. The effects of MEPCM concentration in the slurry and changes in the operating conditions such as the wall temperatures compared to that of pure water have been studied. The MEPCM latent heat and the increased volumetric thermal expansion coefficient during phase change of the MEPCM play a major role in this heat transfer augmentation.

Numerical Characterization of Flow and Heat Transfer in Pre-Swirl Systems

2017 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Cosimo Bianchini ◽  
Jacopo D’Errico
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Numerical Study ◽  
Physical Phenomenon ◽  
Computational Procedure ◽  
Operating Conditions ◽  
Simulation Techniques ◽  
Numerical Characterization ◽  
Unsteady Simulation

This paper deals with a numerical study aimed at the validation of a computational procedure for the aerothermal characterization of pre-swirl systems employed in axial gas turbines. The numerical campaign focused on an experimental facility which models the flow field inside a direct-flow pre-swirl system. Steady and unsteady simulation techniques were adopted in conjunction with both a standard two-equations RANS/URANS modelling and more advanced approaches such as the Scale-Adaptive-Simulation principle, the SBES and LES. The comparisons between CFD and experiments were done in terms of swirl number development, static and total pressure distributions, receiving holes discharge coefficient and heat transfer on the rotor disc surface. Several operating conditions were accounted for, spanning 0.78·106<Reφ<1.21·106 and 0.123<λt<0.376. Overall the steady-state CFD predictions are in good agreement with the experimental evidences even though it is not able to confidently mimic the experimental swirl and pressure behaviour in some regions. Although the use of unsteady sliding mesh and direct turbulence modelling, would in principle increase the insight in the physical phenomenon, from a design perspective the tradeoff between accuracy and computational costs is not always favourable.

scholarly journals Experimental and Numerical Study Effect of Using Nanofluids in Perforated Plate Fin Heat Sink for Electronics Cooling

2018 ◽  
Vol 24 (8) ◽  
pp. 1
Author(s):  
Kadhum Audaa Jehhef
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Volume Fraction ◽  
Numerical Study ◽  
Perforated Plate ◽  
Processing Unit ◽  
Transfer Enhancement

An experimental and numerical investigation of the effect of using two types of nanofluids with suspending of (Al2O3 and CuO) nanoparticles in deionized water with a volume fraction of (0.1% vol.), in addition to use three types of fin plate configurations of (smooth, perforated, and dimple plate) to study the heat transfer enhancement characteristics of commercial fin plate heat sink for cooling computer processing unit. All experimental tests under simulated conditions by using heat flux heater element with input power range of (5, 16, 35, 70, and 100 W). The experimental parameters calculated are such as water and nanofluid as coolant with Reynolds number of (7000, 8000, 9400 and 11300); the air is blown in the inlet duct across the heat sink with Reynolds number of (10500, 12300, 14200 and 16000). The distance fin-to-fin is kept constant at (2.00 mm), and the channel employed in this work has a square cross-section of (7 cm) inside. It was observed that the average effectiveness and Nusselt number of the nanofluids are higher compared with those of using conventional liquid cooling systems. However, the perforated fin plate showed higher air heat dissipation than the other configuration plate fin employed in this study. The experimental results were supported by numerical results which gave a good indication to heat transfer enhancement in studied ranges.  

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