High-Pressure-Cooling-Rig

At up to 2500K, the temperatures in engine combustion chambers are far above the permissible material temperatures of the combustion chamber wall. Intensive cooling of the combustion chamber wall is therefore necessary, for which a considerable proportion of the compressed air is used. Highly efficient cooling concepts with significantly reduced cooling air requirements are needed for future more powerful, more efficient and low-emission engines.

The High-Pressure-Cooling-Rig was developed to investigate the cooling effectiveness of metallic and ceramic combustor wall elements. The test section fits into the HBK 3 test rig and allows the characterization of test objects with original size and under realistic combustor conditions. A combustion chamber is used to produce hot gas at elevated pressures with the typical swirl, turbulence and velocity profile of real combustion chambers. The hot gas is guided into the test section where the test object, e.g. combustor wall element, is placed. The test object is cooled with pre-heated air to create a realistic cooling profile. Thermocouples and heat flux sensors are used to monitor the temperature and cooling effectiveness of the wall element. To determine a two-dimensional temperature distribution of the test object, an infra-red camera can be installed. Optical access to four sides is granted through high pressure windows in the test section.  At different test conditions the influence on the temperature distribution of the wall element is measured and the cooling effectiveness is determined.

Especially lean burn combustors tend to develop thermoacoustic oscillations. The resulting pressure fluctuations impede the cooling effectiveness and reduce the lifetime of combustor parts. To analyse this influence the test rig can also be operated with self-excited pressure oscillations. An additional pressure casing can house tubular combustor cans. In this configuration the test rig is used to investigate prototype combustors made from ceramic matrix composites.

Characteristics

Optical access to hot gas channel from four sides

Three-axis traverse for measurement technique

Research Topics

Development of cooling concepts

Characterization of cooling effectiveness of metallic and ceramic combustor wall elements at realistic operating conditions

Cooling properties under steady-state conditions and under the influence of pressure oscillations

Measurement Technology

2D Laser-Doppler-Anemometry

High speed infrared camera

Unsteady heat flux sensors

Transient pressure transducer

Tecnical Data

  

Static pressure

5..20 bar

Hot gas temperature

1500..1800 K

Hot gas velocity

20..40 m/s

Cooling air temperature of test object

300..700 K

Dimensions of test object

80 x 100 mm²