Narrow Results

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.

In the present work, forced convection heat transfer was investigated numerically for the fully developed fluid flow of incompressible viscous laminar flow under the constant wall heat flux in sudden expansion channels. Various fluids were used with different concentration of nanoparticle such as Al₂O₃, TiO₂, ZnO, CuO, SiO₂. These nanoparticles were dispersed with the range of 0.5–2% volume concentrations in pure water to form stable suspensions of nanofluids. The flow assumed to be uniform in the channel inlet and numerical computations were performed for the fully developed laminar flow conditions. Ansys Fluent 16.1 code, based on finite volume approach was used to calculate the governing continuity, momentum and energy equations. Effect of the Re numbers (100$\le$Re$\le$500), nanoparticle volume concentration (0.5%$\le \phi \le$2.0%) and nanofluid type on the flow and heat transfer characteristics such as convective heat transfer coefficient, Nu number, friction factor and pressure drop has been investigated. Al₂O₃/water nanofluid was found better when compared the other references working fluids by means of heat transfer enhancement.

In the present work, we focus on computational investigations of the Reynolds number effect and the wall heat transfer on the performance of axial compressor during its miniaturization. The NASA stage 35 compressor is selected as the configuration in this study and computational fluid dynamics (CFD) is used to carry out the miniaturization process and simulations. We perform parameter studies on the effect of Reynolds number and wall thermal conditions. Our results indicate a decrease of efficiency, if the compressor is miniaturized based on its original geometry due to the increase of viscous effects. The increased heat transfer through wall has only a small effect and will actually benefit compressor performance based on our study.

COVID-19 is a serious respiratory disease caused by a devastating coronavirus family (2019-nCoV) that has become a global epidemic. It is an infectious virus transmitted by inhalation or contact with the droplet core produced by infected people when they sneeze, cough, and speak. SARS-COV-2 transmission in the air is possible even in a confined space near the infected person. This study examines air conditioners’ effect on the mixed virus and droplets with aerosol disinfectant and gets throughout the elevator to detect the SARS-COV-2, which helps protect passengers’ lives. This study uses fluent 2019R3 software to simulate the virus transmission to model the transient flows numerically. The analysis found that the ventilation system’s turbulent fields can be an effective method of protecting the space from being saturated by the coronavirus.