Destruction of Metallic Obstacles by a Jet of Dilute Polymer Solution

Kudin, A. M.; Баренблатт, Г. И.; Kalashnikov, V. N.; Власов, С. А.; Belokon, V. S.

doi:10.1038/physci245095a0

Cited by 10 publications

(5 citation statements)

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“…In the paper [5] the photographs of wormlike structures in the carboxymethylcellulose (of rather low molecular weight ∼ 70, 000) water solution were presented. An indirect confirmation of visco-elastic behavior of polymeric supramolecular structures was obtained in [6]: a strong water jet directed on a metallic plate did not affect it for hours. Tiny polymer addition leads to a fast abrasive-like wearing of the plate.…”

mentioning

confidence: 85%

A mathematical model of turbulent drag reduction by high-molecular-weight polymeric additives in a shear flow

Баренблатт

2008

Physics of Fluids

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Drag reduction, or the mean velocity increase in a turbulent flow at a fixed pressure drop through the addition of tiny amounts ͑several parts per million͒ of high-molecular-weight polymers ͑Thoms effect͒, has been known already for more than 60 years. Long ago it was understood that this effect is related to supramolecular structures formed in the flow. Recent experiments by Chu, Shaqfeh, and associates, where the motion of supramolecular structures was directly observed, made it possible to understand and quantify the dynamic interaction of the polymeric structures with the solvent ͑water͒ flow. These results lead to the construction of a mathematical model of the Thoms effect, based on the Kolmogorov ͑1942͒-Prandtl ͑1945͒ semiempirical theory of shear flow turbulence. This is the subject of the present letter.Let us first introduce the basic equations of the present work. Turbulent shear flow is considered, so the mean velocity field is assumed to beThe density of the solution is indistinguishable from the water density ; therefore under zero mean mass force the averaged momentum balance equation has the same form as in the absence of the mass force,In these relations the coordinate x 1 is reckoned along the mean flow and the axis x 2 is directed perpendicularly to the wall x 2 = 0. Furthermore, T 12 is the only nonzero component of the Reynolds shear stress, is the shear stress assumed to be constant across the flow, and averaged viscous stress is neglected. The bars denote probability average ͑mean͒ values and the turbulent fluctuations are denoted by primes. The quantity u ‫ء‬ = ͑ / ͒ 1/2 is the dynamic, or friction, velocity.The equation of the turbulent energy balance in the shear flow takes the formHere, unlike in the customary derivations, the mass force is taken into account: F =0; FЈ is the mass force fluctuation. Furthermore, ⑀ is the mean dissipation rate of the turbulent energy into heat,͑4͒ D is the symmetric part of the strain-rate tensor, is the fluid kinematic viscosity, and the summation over repeated Greek indices from 1 to 3 is assumed. The derivation of Eqs. ͑1͒ and ͑2͒ follows the general lines of Ref. 1.The turbulent flow is a cascade of vortices of various scales. The basic Kolmogorov hypothesis 2 ͑see also the paper by Prandtl 3 ͒ can be presented in the following form: At large Reynolds numbers the vortex cascade is self-similar. Hence, all dimensionless flow field properties are universal. According to this hypothesis, all kinematic flow properties are determined by two kinematic properties with different dimensions. Kolmogorov 2 and his direct followers ͑see Ref.1͒ selected as such quantities the local mean turbulent energy per unit mass, b = ͑u 1 Ј 2 + u 2 Ј 2 + u 3 Ј 2 ͒ / 2=u ␣ Јu ␣ Ј / 2, and the local mean length scale of vortices, or the local external length scale of turbulent flow l, which is proportional to it. This hypothesis forms the basis of the ͑b , l͒ semiempirical model. The other possibility is the ͑b , ⑀͒ model which also came into wide use. ͑I used here the origina...

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confidence: 85%

A mathematical model of turbulent drag reduction by high-molecular-weight polymeric additives in a shear flow

Баренблатт

2008

Physics of Fluids

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“…Polyacrylamides (PAM) are the most used polymeric additives in AWJM and shows shear-thinning behavior. 39 It was introduced by Kudin A. M, 40 who observed a significant improvement in terms of cutting and nozzle-wear during submerged-cutting of high-carbon steel. Over the years, various forms of PAM were commercially produced, including Nalco, superwater, Magnoflacc, etc., which were utilized for AWJM processing of foams, 41 marble, 42 rock, 43–44 stainless-steel, 45–47 carbon-steel, aluminum, 48–49 etc.…”

Section: Additivesmentioning

confidence: 99%

A review of additives in abrasive water jet machining and their performance

Sreekumar

Purushothaman

Srinivas

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part J:

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Abrasive Water Jet Machining (AWJM) is an advanced machining process that has a variety of applications, including machining of hard-to-machine materials, drilling, milling, coating removal, polishing, etc. They are attractive because of their versatility, absence of heat-affected zones, low thermal-distortions, low cutting-forces, and environment-friendly nature. However, use of plain-water in AWJM poses some problems due to lack of jet coherence, poor suspension characteristics, and unsatisfactory performances in submerged-cutting and cutting of hollow surfaces. Countering these problems appropriately can lead to better cutting performances in terms of material removal rate, depth of cut, kerf-width, and kerf-taper. It can be achieved with addition of some additives in abrasive water-jet. These additives are mostly polymers of high molecular mass, which increases viscosity, suspension capability, and stability of jet, while reducing drag. In addition to AWJM, the effect of polymeric-additives in other water-based jets like Abrasive-Slurry-Jet (ASJ), High-pressure ASJ, etc. are also discussed. Therefore, this study aims to identify and list of different additives that are used in AWJM and other water-jet-based machining-processes over a past few decades, and to provide a run-through on their performances. It can provide the significant information to researchers working in fields related to waterjets.

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“…Ashworth and Proctor [69] reported that the erosion rates increased when replacing water with polyacrylamide. In [70], it was shown that underwater jet cutting was significantly improved by polymer additions to the jet fluid. In [71], it was observed that the cavitation bubbles in the drag reducing polymer solution appeared larger than those in pure water.…”

Section: Jet Hydrodynamics For Cleaning Applicationsmentioning

confidence: 99%

A Review on the Erosion Mechanism in Cavitating Jets and Their Industrial Applications

et al. 2021

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Cavitating jets have been widely studied for over a century, but despite the extensive literature on this subject, the implementation of cavitating jets in many industries is still very limited due to technical challenges. The main purpose of the present paper is to provide recommendations on using the cavitating jets based on a comprehensive literature review on the erosion mechanism in these jets. Self-resonating jets are extensively discussed in the present paper due to their importance in amplifying the erosion effect of cavitating jets. The influence of different jet nozzle geometric parameters and the operating conditions of the cavitating jet flow on the erosion mechanism is also discussed. Finally, well drilling in addition to multiple other industrial applications of cavitating jets are examined.

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Destruction of Metallic Obstacles by a Jet of Dilute Polymer Solution

Cited by 10 publications

References 1 publication

A mathematical model of turbulent drag reduction by high-molecular-weight polymeric additives in a shear flow

A mathematical model of turbulent drag reduction by high-molecular-weight polymeric additives in a shear flow

A review of additives in abrasive water jet machining and their performance

A Review on the Erosion Mechanism in Cavitating Jets and Their Industrial Applications

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