Simulations of flow and heat conditions in a disc brake are presented in the article. Through simulations different parameters that influence the air flow field were analysed: the size of calculated domain, mesh, boundary conditions and turbulent model. In addition, different ways of applying time-dependent heat source were tested. Simulations with stationary flow field and transient temperature field were compared to a totally trasient simulation. Results show that flow (and consequently heat) conditions in air in case of stationary and transient flow field calculation match relatively well. However in stationary calculation the formation and separation of vortices, that is happening in reality and because of which the actual heat transfer is greater, cannot be seen.
COBISS.SI-ID: 16303894
An experimental study of an axial fan in different operating regimes was performed. The experimental data were acquired using pressure sensors and PIV (Particle Image Velocimetry). The axial fan characteristic curve was divided into its stable and unstable part area. In the unstable area, the rotating stall regime was determined. The location of sudden and deep stall on the characteristic axial fan's curve and the hysteresis area was also determined. Flow fields upstream of the axial fan's rotor and blade passage on three different spans were measured using PIV system.
COBISS.SI-ID: 16304150
The results of numerical simulations can be validated experimentally, but usually only the aggregate characteristics are compared. If the aggregate and partial characteristics can be compared at the same time, the level of trust is increased and the physics can be studied in detail. This paper presents a modular measurement system incorporating several devices, including a PIV, traverse system, NI CompactRIO and/or a DAQ, which are synchronized and enable the simultaneous acquisition of aggregate and partial parameters at various sampling frequencies. The modular concept allows for easy configuration and adjustments as needed. The high DI sampling frequency achieved by the CompactRIO system enabled the analysis of trigger delay and significantly increased the AI capability of the PIV system.
COBISS.SI-ID: 16217622