Line Chilldown

Line Chilldown Using Liquid Hydrogen and Liquid Nitrogen

This validation case compares SINDA/FLUINT and FloCAD® predictions with a 1966 test by the National Bureau of Standards (NBS, now National Institute of Standards and Technology, NIST). In the NBS tests, a pressurized dewar containing either LN2 or LH2 was isolated from an empty 200ft (61m) line (open to the atmosphere) by a valve. At time zero, the valve between the dewar and the line was opened, and cryogenic liquid was allowed to flow until the line was completely full and liquid was discharged from open end of the pipe.

Test Set-up

Comparison with Test Data

Liquid (Normal) Hydrogen, Comparison with Figure 7

Differences between parahydrogen and normal hydrogen are explored, since the exact composition of the hydrogen is unknown. The importance of uncertainties in heat transfer and pressure drop correlations, copper alloy properties (also unknown), dewar pressure, and even the roughness and manufacturing tolerance of the tubing is explored. This study demonstrates automated calibration to test data, and investigation of sensitivities.

Click here to fetch the Cryogenic Cooldown Validation from our User Forum

Download the full Line Chilldown Validation report

See also LNG chilldown of a flexible composite hose

dispersed vs. coalesced front

Tuesday, June 26, 2018, 1-2pm PT, 4-5pm ET

This webinar describes flat-front modeling, including where it is useful and how it works. A flat-front assumption is a specialized two-phase flow method that is particularly useful in the priming (filling or re-filling with liquid) of gas-filled or evacuated lines. It also finds use in simulating the gas purging of liquid-filled lines, and in modeling vertical large-diameter piping.

Prerequisites: It is helpful to have a background in two-phase flow, and to have some previous experience with FloCAD Pipes.

Register here for this webinar