A viscosity correction factor for shear-thinning liquid flows in safety valves

Moncalvo, D.; Friedel, L.

doi:10.1016/j.jlp.2009.10.008

Cited by 7 publications

(2 citation statements)

References 7 publications

(14 reference statements)

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“…To further carry out a research on the influence of concentrations on apparent viscosity, adopting the equation of Ostwald–Dewaele to make an analysis of rheological characteristics []:

normall normaln normalη = normall normaln normalk + ((), normaln - 1) normall normaln normalγ

…”

Section: Resultsmentioning

confidence: 99%

Rheological characteristics of foamed gel for mine fire control

Zhang

Qin

2014

Fire and Materials

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SUMMARYFoamed gel as a new type of fire extinguishing material is used to prevent the spontaneous combustion of coal. In order to make a comprehensive study on rheological characteristics of foamed gel for mine fire control, by using type NDJ-5s digital viscometer, the factors such as mass concentration of the mixture mixed by thickener and crosslinker, foaming multiple, added salts (NaCl, CaCl 2 , AlCl 3 ), pH value and temperature having influences on the rheological properties of foamed gel have been investigated in this paper. It can be found that foamed gel shows the characteristic of non-Newtonian fluids and has shearthinning properties. With increasing of mass concentration of the mixture, the thixotropy response becomes more significant. When the foaming multiple reaches 20, the apparent viscosity gets the maximum value. The obvious viscosity characteristic of 'polyelectrolyte solution' is observed in aqueous salt solutions when added salts are put into the solution. Under different conditions of pH values, foamed gel has higher sensitivity to acid than alkaline. Zero shear viscosity, depending on temperature, decreases with the temperature increasing. Meanwhile, the fire performances of foamed gel are studied experimentally and theoretically.

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“…To further carry out a research on the influence of concentrations on apparent viscosity, adopting the equation of Ostwald–Dewaele to make an analysis of rheological characteristics []:

normall normaln normalη = normall normaln normalk + ((), normaln - 1) normall normaln normalγ

…”

Section: Resultsmentioning

confidence: 99%

Rheological characteristics of foamed gel for mine fire control

Zhang

Qin

2014

Fire and Materials

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“…The authors presented mathematical modelling, simulations and laboratory experiments on an inverted type pilot-operated vent and safety valve. Research on safety valves sometimes also requires the analysis of parameters such as viscosity (Moncalvo and Friedel, 2010), the Reynolds number (Dossena et al, 2017) or pressure oscillations and vibrations (Galbally et al, 2015). This article provides numerical and experimental study of performance of a relief valve used as a safety valve.…”

Section: Introductionmentioning

confidence: 99%

Quality Improvement of a Safety Valve with the Use of Numerical and Experimental Studies

Filo

Domagała

Lempa

et al. 2019

Quality Production Improvement - QPI

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This article presents results of numerical modelling, simulation and test bench experiments of a hydraulic direct-acting relief valve was used as a safety valve. The analyzed safety valve was placed in a system consisting of a fixed-speed pump, a control valve, a hydraulic cylinder as an actuator and a second pressure valve in the load line used as a payload generator for the cylinder. In the first step mathematical model of the system was formulated in the form of a system of ordinary differential equations. Next, simulation model was created in Matlab/Simulink. Simulations were carried out for different values of the actuator payload. The obtained results include time series of pressure, flow rate and displacement of the actuator piston. In order to confirm simulation results, a test bench was built and series of experiments were carried out. High compliance of simulation and laboratory results was obtained. It was confirmed that the proposed solution with the relief valve used as a safety valve fulfills its task of protecting the hydraulic system from excessive pressure increase.

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A Computational Investigation on the Flow of Non‐Newtonian Polymers in Safety Valves

Moncalvo

Friedel

Jörgensen³

2010

Chem Eng & Technol

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At the moment, very little knowledge is available about the flow of shear-thinning media in safety valves. In this paper, the flow of aqueous solutions of polyvinylpyrrolidone with a zero-shear viscosity between 0.3 and 3 Pa s in a LESER Type 441 DN 25/40 safety valve with a lift of 2.2 mm for relieving pressures up to 6.5 bar is computed using ANSYS FLUENT 12. According to these calculations, the lowest values of the dynamic viscosity are reached in the slit between the seat and the disk due to the large local velocity gradients. A more moderate increment in the fluidity of the solutions is observed also in the recirculation zone outside the disk when the stream from the rear of the valve meets the one from the front. A preliminary study suggests that the experimental flows may be turbulent in the slit and then evolve into a laminar profile in the discharge pipe. For this reason, the calculations are carried out assuming laminar, turbulent and transitional flows. The predicted mass flow rates are close to each other and to the measured values, except at relieving pressures close to ambient. The major cause of deviation seems to be the entrainment of air microbubbles, whose elongation may be responsible for additional shearing in the solutions with large polymer weight.

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A viscosity correction factor for shear-thinning liquid flows in safety valves

Cited by 7 publications

References 7 publications

Rheological characteristics of foamed gel for mine fire control

Rheological characteristics of foamed gel for mine fire control

Quality Improvement of a Safety Valve with the Use of Numerical and Experimental Studies

A Computational Investigation on the Flow of Non‐Newtonian Polymers in Safety Valves

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