Low-speed axial diffuser

The low-speed axial diffuser is a 1:10 scale model test rig for the investigation of exhaust gas diffusers. It enables the analysis of complex flow phenomena that are influenced by turbine outflow and support ribs in order to develop more efficient design guidelines.

Description

Areas of application

  • Inlet parameters: Investigation of the influence of inflow parameters on the operating behavior of exhaust gas diffusers

  • Support ribs: Analysis of the effects of support fins on the secondary flow in ring diffusers

  • Optimization: Development of more efficient design guidelines for exhaust gas diffusers

Technical setup and operation

  • Air flow: Ambient air is directed radially-axially into the ring diffuser via a pre-swirl generator, which is optionally equipped with support ribs

  • Trailing vanes: Rotating spoke wheel simulates realistic turbine outflows and generates wake dents

  • Variable parameters: Adjustable parameters such as mass flow, speed, pre-swirl and gap flow to simulate different turbine operating points

  • Calming chamber: Air flows through a conical diffuser into a calming chamber with honeycomb rectifier

Measurement technology

  • Pressure and temperature measurement: Steady and unsteady pressure sensors, temperature measurement technology type K

  • Traversing: Radial traversing with multi-hole flow vector probes and hot-wire probes

  • Flow analyses: 3D CTA and 2D LDA probes for velocity and turbulence measurements

  • PIV: Particle Image Velocimetry for visualizing complex flow fields

Specifications

Mass flow rate 7 kg/s
Mach number at the diffuser inlet 0,1
Reynolds number at the diffuser inlet 4x105
Wake generator max. 3.000 1/min
Various diffuser geometries
Variable angular momentum at the inlet
Variable gap mass and angular momentum flow rate