Cooldown Flow Rate Limits Imposed by Thermal Stresses in Liquid Hydrogen or Nitrogen Pipelines

Novák, J

doi:10.1007/978-1-4757-0513-3_42

Cited by 2 publications

(5 citation statements)

References 4 publications

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“…In addition, temperature gradients in the material or pipe could create undesirable stresses leading to damage and fatigue failures [105]. Only a reduced mass flow can be refueled in the chill-down phase to keep the thermal stress low.…”

Section: Chill-down Of Hose and Reduced Mass Flowmentioning

confidence: 99%

Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

et al. 2022

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Green liquid hydrogen (LH2) could play an essential role as a zero-carbon aircraft fuel to reach long-term sustainable aviation. Excluding challenges such as electrolysis, transportation and use of renewable energy in setting up hydrogen (H2) fuel infrastructure, this paper investigates the interface between refueling systems and aircraft, and the impacts on fuel distribution at the airport. Furthermore, it provides an overview of key technology design decisions for LH2 refueling procedures and their effects on the turnaround times as well as on aircraft design. Based on a comparison to Jet A-1 refueling, new LH2 refueling procedures are described and evaluated. Process steps under consideration are connecting/disconnecting, purging, chill-down, and refueling. The actual refueling flow of LH2 is limited to a simplified Reynolds term of v·d=2.35 m2/s. A mass flow rate of 20 kg/s is reached with an inner hose diameter of 152.4 mm. The previous and subsequent processes (without refueling) require 9 min with purging and 6 min without purging. For the assessment of impacts on LH2 aircraft operation, process changes on the level of ground support equipment are compared to current procedures with Jet A-1. The technical challenges at the airport for refueling trucks as well as pipeline systems and dispensers are presented. In addition to the technological solutions, explosion protection as applicable safety regulations are analyzed, and the overall refueling process is validated. The thermodynamic properties of LH2 as a real, compressible fluid are considered to derive implications for airport-side infrastructure. The advantages and disadvantages of a subcooled liquid are evaluated, and cost impacts are elaborated. Behind the airport storage tank, LH2 must be cooled to at least 19K to prevent two-phase phenomena and a mass flow reduction during distribution. Implications on LH2 aircraft design are investigated by understanding the thermodynamic properties, including calculation methods for the aircraft tank volume, and problems such as cavitation and two-phase flows. In conclusion, the work presented shows that LH2 refueling procedure is feasible, compliant with the applicable explosion protection standards and hence does not impact the turnaround procedure. A turnaround time comparison shows that refueling with LH2 in most cases takes less time than with Jet A-1. The turnaround at the airport can be performed by a fuel truck or a pipeline dispenser system without generating direct losses, i.e., venting to the atmosphere.

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Section: Chill-down Of Hose and Reduced Mass Flowmentioning

confidence: 99%

Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

et al. 2022

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“…• Figure A4.5 shows the maximum LH 2 and LN 2 flow rates to avoid excessive thermal stress from rapid cooling of the thick-wall piping sections such as flanges (Novak 1970).…”

Section: Cooldown Of Cryogenic Systemsmentioning

confidence: 99%

“…A pipeline in which this condition exists may be precooled with gas or slugs of liquid (Novak 1970). A pipeline in which this condition exists may be precooled with gas or slugs of liquid (Novak 1970).…”

Section: Cooldown Of Cryogenic Systemsmentioning

confidence: 99%

“…Upper and lower estimates represent difference in variables such as heat transfer correlation and limiting stress values(Novak 1970). Upper and lower estimates represent difference in variables such as heat transfer correlation and limiting stress values(Novak 1970).…”

mentioning

confidence: 99%

“…Liquid hydrogen flow rate limits to avoid excessive cooldown stresses in thick-wall piping sections such as flanges for 304 SS and 6061 Al. Upper and lower estimates represent difference in variables such as heat transfer correlation and limiting stress values(Novak 1970). t = maximum radial thickness of flange wall (cm) d = inside diameter of flange (cm) Wmax = cooldown flow rate limit (kg/s) Liquid nitrogen flow rate limits to avoid excessive cooldown stresses in thick-wall piping sections such as flanges for 304 SS and 6061 Al.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Guide: Guide to Safety of Hydrogen and Hydrogen Systems (AIAA G-095-2004)

2004

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Cooldown Flow Rate Limits Imposed by Thermal Stresses in Liquid Hydrogen or Nitrogen Pipelines

Cited by 2 publications

References 4 publications

Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication

Guide: Guide to Safety of Hydrogen and Hydrogen Systems (AIAA G-095-2004)

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