Density determination of slush nitrogen by the improved capacitance-type densimeter

Jiang, Yabin; Zhang, P.

doi:10.1016/j.expthermflusci.2010.10.002

Cited by 16 publications

(6 citation statements)

References 14 publications

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“…Liquid nitrogen specific dielectric capacity of is presented in the literature [1,5] as indicated in Table 1. We have also introduced for comparison the specific dielectric capacity of hydrogen.…”

Section: Resultsmentioning

confidence: 99%

“…For these new types of devices slush nitrogen is considered and expected to be a better coolant than sub cooled liquid nitrogen for the hightemperature superconducting cable cooling due to its greater density and cooling capacity. As a consequence of that the coolant consumption and the volume of cooling system are reduced and the stability of cooling system is improved [1].…”

Section: Introductionmentioning

confidence: 99%

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Aspects regarding the liquid level measurement for a cryogenic pump

Ionete

Schitea

Monea

et al. 2012

2012 International Conference and Exposition on Electrical and Power Engineering

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This paper outlines a method of continuous and direct level measurement of cryogenic fluid applicable to a completely immersed cryogenic pump. There are many industrial and scientific processes requiring the knowledge of liquid level in various devices useful for special applications. A particularly case is given by the need of pumping cryogenic liquid from different Dewar vessels with separate locations, as for example at different levels in a building, where a continuous pumping is necessary to cool large conducting cables or large cryogenic installations with forced flow. Ensuring an optimum performance of the cryogenic pump is directly related to the need of measuring the liquid level. In this work a technical solution and its suitability for liquid nitrogen services is presented, together with the proper automation system.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aspects regarding the liquid level measurement for a cryogenic pump

Ionete

Schitea

Monea

et al. 2012

2012 International Conference and Exposition on Electrical and Power Engineering

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“…X(i) and Y(i) are signal values representing capacity variations measured by first and second capacitor, respectively, expressed as a function of time. The function R(τ) reaches the maximum when τ becomes equal to the real transit time of a density pulse (i.e., the time required by a density peak detected by the first capacitive sensor to be also detected by the second capacitive sensor) [14]. The cross-correlation function R(τ) is defined as:…”

Section: Principle Of the Capacitance-type Flowmetermentioning

confidence: 99%

“…Since the dielectric constant of a cryogen, which can be considered ideal, homogeneous and isotropic obeys the Clausius-Mossotti law [12], the density measurement of two-phase mixture can be determined with capacitive methods based on the equation [14]:…”

Section: Principle Of the Capacitance-type Density Measurementmentioning

confidence: 99%

Experimental Investigation and CFD Modeling of Slush Cryogen Flow Measurement Using Circular Shape Capacitors

Monea

Ionete

Spiridon

2020

Sensors

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The measurement of two-phase cryogenic fluid mixtures flow, also known as slush cryogen flow, with its most attractive form (liquid and solid) is of great interest for various applications, due to its thermodynamic advantages. This paper presents a newly developed device, under the form of a circular capacitor prototype, together with an experimental stand for slush formation. Slush nitrogen was used as testing fluid during the experimental work. Then, the experimental data for slush cryogen flow measurement using the proposed circular shape capacitor were compared with theoretical results obtained by simulation. A three-dimensional flow field model was built and solved for the innovative design slush flowmeter using a computational fluid dynamic (CFD) model. Nitrogen slush density of 874 kg/m 3 , representing approximately 30% solid fraction, was reported for both the modeling and experimental testing, although the numerical investigation is not limited to these values. By comparing experimental vs. simulation results, a deeper view on the designed configuration can be achieved, thus improving the progress in producing high-performance next generation devices for two-phase flow measurement in terms of physical dimensions, length and space between armatures. Even so, the mathematical model has limitations when mixtures with higher percentages of solid phase and particle sizes are encountered.

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“…Current measurement systems for cryogenic environments use gamma-ray-based (Carapelle and Colette, 2005), microwave-based (Ohira, 2004), radio-frequency-based (Filippov et al, 2013), resistive, or capacitive (Jiang and Zhang, 2011) principles. Some of them intrude into the volume under investigation, and some can lead to a local heat input or other parasitic effects (Mukhopadhyay, 2010).…”

Section: Introductionmentioning

confidence: 99%

Capacitive gas-phase detection in liquid nitrogen

Kandlbinder

Fischerauer

Mösch

et al. 2017

J. Sens. Sens. Syst.

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Abstract. The main and upper stages of heavy lift launchers for space applications are often fuelled by cryogenic liquids. In order to enable the re-ignition of a cryogenic upper stage for orbital changes, it is crucial to study the behaviour of these fluids in microgravity. As gaseous bubbles entering the fuel lines of the engine can cause the destruction of the engine, these bubbles are a risk for the functionality of the re-ignition mode. To measure an evolving gaseous phase and its volume, a capacitive measurement system for two-phase mixtures was realised. Its electrodes are arranged in such a way that phase changes inside a vessel can be detected without parasitic heating under cryogenic conditions. Two cases have been investigated: a fill-level measurement involving a large gas bubble above a homogenous liquid on the one hand, and the identification of a bubble stream inside a liquid on the other hand. The system concept was tested in a cryogenic environment allowing the controlled generation of bubble streams inside liquid nitrogen and of a contiguous gaseous volume above the liquid. The characteristics of the measurable capacitances of different pairs of electrodes were experimentally determined and compared with finite-element simulations (Ansys). In addition, the electrical flux density was computed to corroborate the simulated capacitance curves with theoretical statements. The experimental findings closely agree with the simulated results if possible disturbances due to the characteristics of the capacitance measurement hardware are properly taken into account. Thus, by measuring various capacitances, it was possible to determine the level up to which a receptacle inside a liquid-nitrogen tank was filled with liquid (the space above the liquid being taken up by gaseous nitrogen), to identify the existence of a bubble stream in the liquid nitrogen and to demonstrate that the capacitance measurement results enable one to differentiate between the two cases.

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Density determination of slush nitrogen by the improved capacitance-type densimeter

Cited by 16 publications

References 14 publications

Aspects regarding the liquid level measurement for a cryogenic pump

Aspects regarding the liquid level measurement for a cryogenic pump

Experimental Investigation and CFD Modeling of Slush Cryogen Flow Measurement Using Circular Shape Capacitors

Capacitive gas-phase detection in liquid nitrogen

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