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1

Effects of U-shaped two-step throttling groove parameters on cavitation erosion characteristics

Jia Wenhua, Liu Yanyan, Yin Chenbo, Li Guo, Zhu Dasheng, Ding Shen

Journal of Theoretical and Applied Mechanics

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2021

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Vol. 59 nr 4

529--538

EN

Throttling usually occurs when a fluid passes through an orifice, sometimes even severe cav- itation erosion may occur. In this study, the equation for the cavitation index of a throttling valve was proposed and the cavitation erosion area in the throttle valve was found to change its position with the orifice opening (X). Cavitation features of singular and two-port se- ries throttling grooves were characterized by defining cavitation indexes σ1and σ2, because the cavitation index-σ can determine the occurrence and intensity of cavitation. Then the indexes σ1 and σ2 included internal geometric parameters and external pressure boundaries were obtained, and cavitation indexes curves σ1-X and σ2-X were also plotted. From the curves of the cavitation index, it was observed that cavitation concentration section also would transfer with opening X changes in the U-shaped groove. The depth of the U-shaped groove had a more evident impact on cavitation, whereas the effect of width on cavitation erosion was not so obvious. The intensity of cavitation erosion when the fluid flowed into the orifice section of the U-shaped groove was always larger than that when the fluid flowed away.

2

The Method of Removal Yttrium (III) and Ytterbium (III) From Dilute Aqueous Solutions

Lobacheva O., Dzhevaga N., Danilov A.

Journal of Ecological Engineering

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2016

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Vol. 17, nr 2

38--42

EN

Yttrium (III) and ytterbium (III) cations ion flotation from diluted aqueous solutions in the presence of chloride ions using sodium dodecyl sulfate as collector agent were studied. Y (III) and Yb (III) distribution and recovery coefficients as a function of aqueous phase рН value at different sodium chloride concentrations were received. Yttrium (III) and ytterbium (III) chloro and hydroxo complexes instability constants were calculated. The calculation of separation coefficient at рН specified values depending on chloride ion concentration was conducted. Maximum separation coefficient was observed when chloride concentration of 0.01 M is 50 at рН 7.8. Ksep is minimal in nitrate medium ans is 3 at рН 7.0. At sodium chloride concentration of 0.05 М Ksep is 9 at рН 7.8.

3

The characteristics of two-phase 22Cr-6Ni-2Mo-1,5Cu cast steel

Kalandyk B.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 4

61-64

EN

The paper discusses the effect of the casting wall thickness on the segregation of alloying elements in two-phase (F-A) 22Cr-6Ni-2Mo-1,5Cu cast steel. The values of the distribution coefficient k0 for Cr, Mo, Si, and Ni, Mn, Cu in the cast stepped test piece walls of three different thicknesses were determined. After solutioning, the values of Rm, R0,2, A5 and Z were measured in the wall of 45 mm thickness and were compared with the results obtained for austenitic cast steel of 18Cr-9Ni grade. In the examined cast steel also the content of [delta] ferrite and the value of PRE_N were determined.

4

The distribution of traces during the crystallization of barium chloride

Korolewicz T., Wójcik J.

Polish Journal of Applied Chemistry

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2000

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Vol. 44, nr 2-3

159-166

EN

The paper deals with investigations on the distribution of trace amounts of sodium, potassium, calcium and strontium ions in the course of the fractionated precipitation of barium ions from a solution of barium chloride by means of hydrochloric acid. The effects of this operation were determined by making use of the method of radioactive traces applying isotopes of( 24)Na, (42)K, 45Ca and 85Sr. The percentage of trace elements co-precipitated with the sediment of barium chloride is only slight. After the precipitation of about 70% of the matrix, within the investigated range of concentrations of the traces 1 x 10(-4)-1 x 10(-3) % recalculated into solid BaCl(2), there are 99% of the initial amount of sodium, 95-98% potassium, 95-99.5% calcium, 94-96% strontium. Investigated was also the distribution of Cd(II), Co(II), Cu(II), Fe(III), Mn(II), Ni(II), Pb(II), T1(I) and Zn(II) in the course of a single separation of BaCl2 by means of hydrochloric acid. The trace amounts of heavy metals were analysed by means of the AAS-method. After the precipitation of about 70% of the matrix, within the investigated range of concentrations of the traces 5xlO(-5)-5x1O(-3) % most of the trace elements are contained in the solution. Only lead ions co-precipitate in such conditions with the sediment of barium chloride. The obtained results have made it possible to apply the operation described above as one of the stages of purification in the course of winning and analysing spectrally pure BaCl(2).