Development of a simple calculation method for the conductance of rarefied gas flow in cylindrical pipe applicable to divertor exhaust investigation of nuclear fusion reactor

ABSTRACT

A gas pressure distribution calculation method for viscous laminar and intermediate flows is developed. By introducing the pseudo-conductance for viscous laminar flow, linearized equations describing pressure distribution are obtained. In intermediate flow, the pressure distribution is iteratively obtained. The validity of the method is confirmed by demonstrating a pressure in a long-tube flow path with various flow rates. The result smoothly connects theoretical curves of molecular flow and viscous laminar flow between two regions. Then, the calculation method is applied to an actual device and is compared to the measurement. The comparison between the calculation and measurement shows the qualitative agreement and reveals the requirement for a more detailed implementation of the actual conditions.

KEYWORDS:

• Intermediate flow
• viscous laminar flow
• Knudsen number
• rarefied gas flow
• divertor exhaust
• DEMO

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

The work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI [Grant No. JP19H01869] and [Grant No. JP23H01146]; The Hibi Science Foundation.