Void fraction and speed of sound measurement in cavitating flows by the three pressure transducers (3PT) technique

Esposito, Claudia; Yenigun, Onur; Gouriet, Jean‐Baptiste; Steelant, Johan; Vetrano, Maria Rosaria

doi:10.1016/j.expthermflusci.2019.109949

Cited by 8 publications

(5 citation statements)

References 35 publications

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“…Moreover, no energy transport equation is solved. This represents a strong simplification of the problem, since it has been proved in a previous work [5] that the variation of the thermo-physical properties of the materials can influence the results of the simulation. Despite this, it has been decided that for this application, the incompressibility hypothesis is acceptable since from the experiments no large temperature gradients are observed.…”

Section: Numerical Model and Setupmentioning

confidence: 99%

Experimental and Numerical Study of a Cryogenic Ball Valve Using Liquid Nitrogen

Scelzo¹,

Faruoli²,

Lejeune³

et al. 2023

World Congress on Momentum, Heat and Mass Transfer

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This paper addresses the experimental and numerical study of a cryogenic ball valve using liquid nitrogen as working fluid. Experimental tests were performed in the Cryoline facility at the von Karman Institute for Fluid Dynamics (Belgium) in collaboration with Centre Technique des Industries Mécaniques (France). Mass flow rate, pressure, and temperature measurements were performed during the tests, and synchronized with high-speed flow visualization. Subcooled liquid nitrogen was ensured upstream the valve. Three different valve apertures, with different back pressure values, enabled both fully liquid and two-phase flow conditions downstream the valve. Besides the flow regime and the hydraulic performance, the valve stem temperature was monitored during the tests and the subsequent accelerated transient warming of the cryogenic line. In parallel, isothermal CFD simulations were performed in OpenFoam using a standard cavitation model. Results in single and two-phase flow conditions are compared to the experimental findings.

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Section: Numerical Model and Setupmentioning

confidence: 99%

Experimental and Numerical Study of a Cryogenic Ball Valve Using Liquid Nitrogen

Scelzo¹,

Faruoli²,

Lejeune³

et al. 2023

World Congress on Momentum, Heat and Mass Transfer

View full text Add to dashboard Cite

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“…Nevertheless, these probes are impacted by thermal effects and are still in a phase of performance evaluation. Therefore, we preferred to use the 3PT technique that only depends on pressure and, applied to isothermal cavitation [39] , it provided space and time average values of the speed of sound. Besides, the 3PT technique can be easily applied and this is indeed a big advantage for cryogenic applications where the thermal properties of the liquid narrow the possible techniques to apply.…”

Section: The 3pt Techniquementioning

confidence: 99%

“…The distance between the three sensors has to be accurately chosen to maximize the sensitivity and the robustness of the technique. In our experimental set-up, the optimal distance ( L ) was selected using the approach reported in [39] and is equal to six times the pipe diameter D .…”

Section: The 3pt Techniquementioning

confidence: 99%

See 1 more Smart Citation

On the influence of thermal phenomena during cavitation through an orifice

Esposito

Peveroni

Gouriet

et al. 2021

International Journal of Heat and Mass Transfer

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Thermal properties of cryogenic fluids can profoundly change the nature of cavitation since the fluid pressure drop is not, anymore, the only driving parameter of this phenomenon.In this research, we have conducted experiments inducing cavitation via a cylindrical orifice using Liquid Nitrogen as working fluid and exploring cavitation regimes going from bubbly cavitation to full flashing. Among others, we performed unsteady pressure measurements to derive the speed of sound during cavitation and high-speed imaging to understand the evolution of the two-phase flow along the pipe.In our analysis we use five dimensionless numbers to describe the flow conditions upstream and downstream of the orifice, and the type of transition taking place across the orifice.In this paper, we show that the fluid initial subcooling level T sub upstream of the orifice and the superheat level Rp of the flow downstream of the orifice are two parameters essential to take into account the metastability of the fluid. Therefore, we propose a new semi-empirical model for predicting the effect of the fluid thermal properties on cavitation. Specifically, we define a parameter T which, multiplied by the saturation pressure at the inlet temperature, allows us to estimate the pressure reached at the orifice to cavitate.

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“…Other techniques are based on the variation of the electrical impedance of the mixture as the vacuum fraction varies [4,5,6]. In some cases, these techniques are associated with high-speed photography [7] in transparent experimental pipes, or with the introduction of optical fibers inside the pipe [8].The alteration of the speed of sound as a function of the vacuum fraction can be related to the specific two-phase flow pattern by means of pressure transducers [9].Even thermometry and infrared analysis can give interesting results in the detection of anomalous conditions of two-phase flow [10,11].Last but not least is the technique based on the analysis of the vibrations induced by the two-phase flow on the pipe [12]. Vibration can be decoded by identifying characteristic frequencies by Fourier analysis or used by more sophisticated statistical techniques [13].This work presents a methodology for identifying the different two-phase flow patterns starting from vibrational data acquired using accelerometers, but processed using an innovative technique based on discriminant analysis.…”

Section: Introductionmentioning

confidence: 99%

Recognition of two-phase flow pattern inside evaporator tubes

et al. 2021

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The convective heat exchange mechanism in two-phase regime, can allow high exchange coefficients, as long as particular conditions are respected, in terms of vapor quality. In evaporator tubes this problem is particularly important as a deviation from the optimal flow conditions can drastically drop the efficiency of the heat exchange. This work describes an innovative methodology for identifying the different two-phase flow regimes in evaporator pipes, through the processing of the vibrational data acquired on the pipe itself. An experimental apparatus with transparent pipes has been built up to recognize flow patterns by a fast image acquisition camera. Images have been associated to vibration data acquired on pipes by accelerometer. The analysis of frequency spectrum, led to first interesting results thus it is possible to distinguish between “no bubbles” regimes and different “bubbles” regimes. A wide test campaign has been realized on vertical and horizontal pipes, simulating steam bubbles with nitrogen bubbles, reproducing the main flow patterns. The paper demonstrates the possibility to design smart and non-intrusive sensor to be applied on evaporated tubes for the recognizing of anomalous thermal flow condition and sets the stage for future engineering work.

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Void fraction and speed of sound measurement in cavitating flows by the three pressure transducers (3PT) technique

Cited by 8 publications

References 35 publications

Experimental and Numerical Study of a Cryogenic Ball Valve Using Liquid Nitrogen

Experimental and Numerical Study of a Cryogenic Ball Valve Using Liquid Nitrogen

On the influence of thermal phenomena during cavitation through an orifice

Recognition of two-phase flow pattern inside evaporator tubes

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