|
|
Assessment of Various Converging Inlet Nozzles for Wind Tunnel Using CFD
Kosiak, Pavlo ; Radnic, Tomáš ; Mamula, Milan ; Hála, Jindřich ; Šimurda, David ; Luxa, Martin
A new calibration tunnel intended for pressure probe calibration is being designed at the Aerodynamic Laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences (IT CAS). A critical part of the design is the converging nozzle since it can substantially affect the resulting flow field in the test section. Three types of nozzles were chosen for the CFD investigation: two-sine, Vitoshinski, and Vagt. For each type of nozzle, two configurations were considered: long (645 mm) and short (353mm). Flow of the viscous, compressible fluid through all the variants was simulated using Ansys CFX commercial software. Results proved the Vagt nozzle to have the most uniform velocity profile and zero curvature at its end making it the most suitable for the intended use.
|
|
| |
|
|
Measurements on Turbine Cascade KOBRA
Luxa, Martin ; Hála, Jindřich ; Šimurda, David
The report contains results and evaluation of aerodynamic measurement on a blade cascade representing the section imitating the conical stream line in the last rotor row of a gas trubine under considerable off-design condition. The research report contains detailed specifications of the measured model, overview of the results of the optical measurements (interferometry, schlieren method in Toepler configuration) and pneumatic measurements (traversing with five hole conical probe downstream the cascade).
|
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
CFD Analysis of Flow in a Blade Cascade Deformed Due to Forced Torsional Vibration
Vomáčko, V. ; Šidlof, P. ; Šimurda, David ; Hála, Jindřich
The paper presents a 3D numerical simulation of flow in a blade cascade, whose geometry models the test section of a new experimental facility for blade flutter research. In the experimental setup, the middle blade of the cascade undergoes high-frequency forced sinusoidal pitching oscillation. Due to inertial forces, the slender blade deforms elastically to certain degree. The goal of this study is to assess the influence of the elastic deformation on the flow field. To compute the deformed geometry, a transient structural analysis was performed. In the second part, the CFD model of flow past a 3D blade cascade with deformed and undeformed blade is presented and these two configurations are compared. For the deformed configuration the incidence angle increases along the blade span from -1.8° to -2.7°. However, the Mach number distribution along the span varies less than expected. blade cascade, flutter, turbomachinery, CFD
|
|
|
Creation and Validation of Pressure Loss Model for Steam Turbine Control Valves
Sláma, V. ; Mrozek, L. ; Tajč, L. ; Šimurda, David ; Hála, Jindřich
In this paper, a creation and a validation of the pressure loss model for the specific and widely used design of the steam turbine inlet control valve assembly called an L-valve is described. This model is based on a wide range of experimental measurements on the valve model installed in an air tunnel and it is validated by numerical simulations using the commercial code. The results of experimental measurements as well as numerical simulations are shown. Furthermore, differences between experimental and numerical results are discussed. According to the results, the pressure loss model in the form of a smart and effective procedure for calculating the valve assembly pressure losses and choosing an optimal valve sizes has been created.\n
|
host ::
RSS.