Wyniki wyszukiwania - BazTech

1

Investigating the effect of insoluble additives type on the drag reduction performance in a crude oil turbulent flow system

Mahmood Wafaa Kamil, Abdulbari Hayder A., Laft Asaad H.

Acta Innovations

|

2022

|

no. 43

44--53

EN

In the present work, the effect of three insoluble additives densities on reducing the drag of crude oil was investigated. The objective of the present work is to evaluate the effect of the insoluble additive’s densities on their drag reduction efficiency in hydrocarbon flow medium. Three powders with different densities are chosen, namely carbon powder, glass powder, and copper powder, with a density of 1710 kg/m3 , 2550 kg/m3 , and 8950 kg/m3 , respectively. The turbulence flow environment was created in a custom-made rotating disc apparatus with a maximum rotation speed of 300 rpm. To evaluate the effect of the powder density, the particle's size was chosen to be 100 µm. All the solutions were tested at the exact operating conditions with a rotation speed ranging between 200 to 2200 rpm. The experimental results showed a clear effect of the powder density on the drag reduction performance. The glass powders showed the highest drag reduction effect, while the copper and carbon powders were lower. The effect of the degree of turbulence on the drag reduction performance of the powders was clear, where the interaction between the powders and the turbulence structures (eddies) governed the turbulence-suppression efficiency of the additives.

2

Laboratoryjne badania oporów toczenia taśmy po krążnikach

Gładysiewicz L., Woźniak D., Konieczna M.

Transport Przemysłowy i Maszyny Robocze

|

2017

|

Nr 2

22--26

PL

Doskonalenie transportu taśmowego skupia się obecnie w coraz większym stopniu na obniżeniu energochłonności przy realizowaniu złożonych zadań transportowych. Obniżenie energochłonności przenośników taśmowych w bezpośredni sposób redukuje koszty eksploatacyjne. Aby zrealizować konkretne rozwiązania energooszczędne, konieczne jest prowadzenie zarówno analiz teoretycznych, jak i zaawansowanych badań laboratoryjnych. Od kilkunastu lat kwestia redukcji oporów ruchu, a więc redukcja energii absorbowanej przez przenośniki taśmowe, jest przedmiotem badań w wielu ośrodkach naukowych [3]. Większość metod badawczych wymaga rozbudowanych stanowisk z napędzaną pętlą taśmy.

EN

Nowadays improvement of belt conveyors focused on reducing energy consumption during complex conveyor work. Lowering the energy consumption is directly connected with the reduction of maintenance costs of conveyors. To achieve this aim it is necessary to conduct both theoretical analyzes and increasingly rigorous laboratory tests. Reduction of movements resistance (reduction of energy consumption of conveyors) is matter of research activities for many years [3]. Most of known methods requires complicated test rigs with driven belts loop. Method presented by the authors allows to conduct the laboratory test of rolling resistance in easier way. Measurements in new test rig model the process of rolling idler on track covered by sample of a belt. In this paper the new method of measurements of rolling resistance in a laboratory was shown. It allows to analysed the impact of construction of belts (construction of cord or thickness of belts cover). Survey impact of temperature, frequency of shifting of idler and different loading on rolling resistance are also possible. The paper presents the results of measurements rolling resistance for various types of belts applying different loading.

3

Anomalne zjawisko przepływowe wywołane dodatkami polimerowo-micelarnymi

Matras Z., Walczak S.

Inżynieria Chemiczna i Procesowa

|

2006

|

T. 27, z. 3/1

965-974

PL

Przedstawiono zjawisko redukcji oporów przepływu przez jednoczesne dodanie do rozpuszczalnika wielkocząsteczkowego polimeru i substancji powierzchniowo czynnej. W takim przypadku strefa przejścia między ruchem laminarnym i turbulentnym jest znacznie rozszerzona i przesuwa się w kierunku większych liczb Reynoldsa w porównaniu z przypadkami dodania do rozpuszczalnika jedynie polimeru lub wyłącznie substancji powierzchniowo czynnej. Przedstawiono i przeanalizowano wstępne wyniki badań doświadczalnych.

EN

The phenomena of drag reduction by means of surfactant and high molecular polymer added simultaneously to the solvent are presented and discussed. It appears that transition zone between laminar and turbulent flow extends towards larger Reynolds numbers in comparison with those occurring in the case of high molecular polymer or surfactant added separately. Initial experimental results are presented and examined.

4

Effect of elbows and sudden contraction of cross-section on drag reduction effect in surfactant solution flowing in pipe system

Broniarz-Press L., Różański J., Szczecina T.

International Journal of Applied Mechanics and Engineering

|

2005

|

Vol. 10, no spec

69-75

EN

The effect of the local frictions on drag reduction in a flow of surfactant solutions in the pipeline system has been studied. The experimental tests for aqueous solutions of hexadecyltrimethylammonium chloride of the concentration of 50, 100 and 150ppm, have been carried out. The flow in straight tubes as well in the pipeline system elements such as elbows and sudden contraction in cross-section has been tested. On the basis of the experimental data it was shown that the presence of the elements giving the local resistances in the pipeline system will bring about the decrease in flow drag reduction effect. The effect can be explained by existing in the systems tested the additional stresses caused by the constructional elements. The additional stresses cause the partial destruction of the shear induced structure SIS (responsible for the flow stabilization) and the decrease of the drag reduction effect.

5

Metoda obliczania oporów przepływu gaz-ciecz-ciecz

Troniewski L., Dyga R.

Inżynieria i Aparatura Chemiczna

|

2003

|

Nr 6

3-5

PL

W pracy przedstawiono, opracowaną na podstawie własnych badań doświadczalnych, metodę obliczania oporów przepływu gaz-ciecz-ciecz. Zaproponowana metoda może znaleźć zastosowanie w inżynierskich pracach projektowych.

EN

The method for pressure drop calculation in gas-liquid-liquid systems, and elaborated on the basis of our own investigations is presented. The method proposed can be used in designing.

6

pH effect on rheological properties of surfactant solutions in hard water

Broniarz-Press L., Różański J., Bednarz J.

International Journal of Applied Mechanics and Engineering

|

2003

|

Vol. 8, no spec.

201-206

EN

In the paper the results of experiments on the both, salt and pH effect, on the rheological properties of surfactant solutions (in hard and distilled water) are presented. Three surfactants were used: hexadecyltrimethylammonium bromide (cationic), sodium oleate and potassium oleate (anionic). The special additives were sodium salicylate (NaSal), calcium and magnesium chloride, sodium sulphate, sodium phosphate as well as sodium hydroxide, hydrochloric acid of various concentrations. The studies showed the existing for a given solution the optimal pH value connected with both, the maximum of a viscosity and formation of the shear induced structure SIS. The effect of ions and pH depends on the kind of surfactant/solvent system. It has been shown that the effect of the pH of water on the rheological properties of the solutions studied is more evident for sodium oleate than for HTAB/NaSal.

7

Characteristics of the flow of the surfactants solutions in the curved pipes

Broniarz-Press L., Różański J., Dryjer S., Woziwodzki S.

International Journal of Applied Mechanics and Engineering

|

2003

|

Vol. 8, no spec.

135-139

EN

In this paper a number of flow experiments in curved tubes with aqueous solutions of the both, cationic and anionic, surface-active agents are presented. It has been shown that taking into account the flow criterion for power-law fluids by Metzner and Reed in the definition of modified Dean number for curved tube is more correct than the use of Reynolds number for clear solvent. The drag reduction in the coils was observed not only in the turbulent flow, but also in the pseudolaminar one. It has been stated that the curvature effect on friction factor for surfactant solutions exists below the critical value of modified Dean number. The value of is higher than this one characteristic for the clear solvent, and linearly increases when geometric modulus decreases.

8

A new description of "diameter effect" in pipe flow of surfactant solutions

Broniarz-Press L., Różański J.

International Journal of Applied Mechanics and Engineering

|

2003

|

Vol. 8, no spec.

127-133

EN

On the basis of our experimental investigations it was found that proximate causes of an appearance of scale effect should be connected with rheological properties of surfactant solutions and especially with the critical value of shear rate above which the formation the fluid structure of SIS follows. If the value of critical shear rate becomes exceeded in the laminar range of flow, the system achieves the maximal drag reduction in a flow for a given surfactant solution. In case when it takes place in the turbulent range, at a given value of Reynolds number in the pipe of bigger diameter the smaller decrease of friction factor has been observed. We propose for description of "diameter effect" the relation between DR or DDR factors and dimensionless velocity wr.

9

Straty energetyczne w przepływach roztworów micelarnych

Matras Z., Głód J.

Prace Naukowe Instytutu Techniki Cieplnej i Mechaniki Płynów Politechniki Wrocławskiej. Konferencje

|

2000

|

Vol. 56, nr 10

145-152

PL

W pracy podjęto próbę rozwiązania zagadnienia obliczania strat ciśnienia przy przepływie roztworów micelarnych w gładkich przewodach o przekroju kołowym. Wykazano doświadczalnie, że krzywe oporów roztworów micelarnych, przedstawione w pseudonewtonowskim układzie liczb kryterialnych [ReM, cfM], są identyczne z krzywymi oporów cieczy newtonowskich zarówno w zakresie laminarnym, jak i turbulentnym. Ustalono, że strefa przejściowa między przepływem laminarnym a turbulentnym dla roztworów micelarnych jest wydłużona w kierunku większych liczb Reynoldsa, w stosunku do strefy jaka występuje w przepływie klasycznych, reostabilnych cieczy nienewtonowskich. Zaproponowano empiryczną zależność określająca krytyczną wartość liczby Reynoldsa ReM2, której odpowiada minimalna wartość współczynnika oporów cfM, a jednocześnie przekroczenie której powoduje nagły wzrost oporów przepływu. Zarówno badania reologiczne, jak i badania oporów przepływu wykonano przy użyciu specjalnie zaprojektowanego reometru kapilarno-rurowego.

EN

In this paper, the experimental results of frictional losses of the micellar (surfactant) solutions in pipes of different diameters have been presented. It was experimentally proved that friction curves of micellar (surfactant) solutions, presented in a system pseudo-Newtonian dimensionless numbers [ReM, cfM] are identical with the friction curves of Newtonian fluids, both in laminar as well as turbulent zone. It was determined that the transition zone between laminar and turbulent flow, in case of micellar solutions is extended towards larger Reynolds's numbers, compared to the one occurring in case of the flow of classical purely-viscous non-Newtonian fluids. Empirical relationship defining the critical value of a Reynolds's number ReM2, respective to a minimum value of friction factor cfM has been proposed. Exceeding this value causes sudden growth in frictional losses.