caa a22 4500 465814247 CHVBK 20180323112123.0 cr unu---uuuuu 170327e19900901xx s 000 0 eng 10.1007/BF01376796 doi (NATIONALLICENCE)springer-10.1007/BF01376796 Experimental investigations of the stability limit of the helical flow of pseudoplastic liquids [Elektronische Daten] [S. Wroński, M. Jastrzębski] The stability of the laminar helical flow of pseudoplastic liquids has been investigated with an indirect method consisting in the measurement of the rate of mass transfer at the surface of the inner rotating cylinder. The experiments have been carried out for different values of the geometric parameterη = R 1/R 2 (the radius ratio) in the range of small values of the Reynolds number,Re < 200. Water solutions of CMC and MC have been used as pseudoplastic liquids obeying the power law model. The results have been correlated with the Taylor and Reynolds numbers defined with the aid of the mean viscosity value. The stability limit of the Couette flow is described by a functional dependence of the modified critical Taylor number (including geometric factor) on the flow indexn. This dependence, general for pseudoplastic liquids obeying the power law model, is close to the previous theoretical predictions and displays destabilizing influence of pseudoplasticity on the rotational motion. Beyond the initial range of the Reynolds numbers values (Re>20), the stability of the helical flow is not affected considerably by the pseudoplastic properties of liquids. In the range of the monotonic stabilization of the helical flow the stability limit is described by a general dependence of the modified Taylor number on the Reynolds number. The dependence is general for pseudoplastic as well as Newtonian liquids. Steinkopff, 1990 F low s tability nationallicence h elical f low nationallicence v ortices nationallicence p seudoplastic l iquid nationallicence C ouette f low nationallicence C i : concentration of reaction ions, kmol/m3 nationallicence d = R 2 − R 1 : gap width, m nationallicence F M (η) : Meksyn's geometric factor (Eq. (1)) nationallicence F 0 : Faraday constant, C/kmol nationallicence i l : density of limit current, A/m3 nationallicence k c : mass transfer coefficient, m/s nationallicence n : flow index nationallicence R 1, R 2 : inner, outer radius of the gap, m nationallicence Re = V m ·2d·ϱ/µ m : Reynolds number nationallicence Ta c = ω c ·d3/2· R 11/2·ϱ/µ m : Taylor number nationallicence Z i : number of electrons involved in electrochemical reaction nationallicence η = R 1/ R 2 : radius ratio nationallicence µ : apparent viscosity (local), Ns/m2 nationallicence µ m : mean apparent viscosity value (Eq. (3)), Ns/m2 nationallicence µ i : apparent viscosity value at a surface of the inner cylinder, Ns/m2 nationallicence ϱ : density, kg/m3 nationallicence ω c : angular velocity of the inner cylinder (critical value), 1/s nationallicence Wroński S. Institute of Chemical and Process Engineering, Warsaw University of Technology, 1 Waryńskiego Street, 00-645, Warsaw, Poland aut Jastrzębski M. Institute of Chemical and Process Engineering, Warsaw University of Technology, 1 Waryńskiego Street, 00-645, Warsaw, Poland aut Rheologica Acta Steinkopff-Verlag 29/5(1990-09-01), 453-461 0035-4511 29:5<453 1990 29 397 https://doi.org/10.1007/BF01376796 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01376796 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wroński S. Institute of Chemical and Process Engineering, Warsaw University of Technology, 1 Waryńskiego Street, 00-645, Warsaw, Poland aut NATIONALLICENCE 700 1- Jastrzębski M. Institute of Chemical and Process Engineering, Warsaw University of Technology, 1 Waryńskiego Street, 00-645, Warsaw, Poland aut NATIONALLICENCE 773 0- Rheologica Acta Steinkopff-Verlag 29/5(1990-09-01), 453-461 0035-4511 29:5<453 1990 29 397 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer