COSMOS-H (under construction)
Critical heat flux On Smooth and MOdified Surfaces – High pressure loop
The COSMOS-H facility is being built for the experimental investigation of flow boiling- and other complex flow phenomena possibly occurring in nuclear power plants. Initially it will be used in the context of the Nuclear Safety Research by the group Accident Analysis at the Institute for Nuclear and Energy Technologies (IKET). After commissioning of the facility, physical phenomena like flow boiling are studied under prototypic thermodynamic conditions with pressures up to 170 bar (17 MPa) and temperatures up to 360°C. The facility permits a heating power of 2 MW for heating and evaporation. It uses liquid water and steam as working fluid.
Figure 1: CAD model of the high-pressure facility, view from the north
Besides investigations of boiling phenomena COSMOS-H allows the study of other issues related to heat transfer, and material and component testing in the field of power plant engineering, and chemical and process engineering. The special quality of the experimental results is assured by the unique instrumentation of the water loop and test section in combination with high pressures and temperatures.
Table 1 - Design parameters
In cooperation with the Institute of Chemical Engineering (TVT), measurements for the development and validation of new CFD methods will be performed as part of the project NUBEKS. The objective is the visualization and recording of flow conditions at the onset of boiling crisis under reactor typical conditions. Therefore the TVT is currently building a modular high-pressure test section with extensive instrumentation.
Figure 2: CAD model of the high-pressure facility, view from the west
The modular test section will be equipped with a large number of thermocouples and pressure sensors as well as windows, which will provide a direct optical access to the flow. These sight glasses will be used for high-speed imaging and optical measurements like LDA or PIV. For the NUBEKS experiments the test section will be equipped with a single heated rod in an annular gap; in the course of the project it is planned to perform measurements at a rod bundle.
Figure 3: CAD model of the test section