Determination of the flow and heat transfer characteristics in non-Newtonian media agitated using the electrochemical technique

Experimental Modelling of Local Heat Transfer Process for a Gas-liquid System in an Agitated Vessel with the System of A 315 – RT ImpellersExperimental Modelling of Local Heat Transfer Process for a Gas-liquid System in an Agitated Vessel with the System of A 315 – RT Impellers

“…Distributions of the heat transfer coefficient on the side of the fluid in a jacketed, baffled agitated vessel strongly depend on the impeller type. This statement confirms the results of local heat transfer obtained for different single impellers, (for example, centrally located Rushton turbine 12,18,19,29 , six-bladed PBT 30,31 , Pfaudler 32,33 , HE 3 23,24 , CD 6 26,27 , four-bladed pitched paddle 19 or MR210 impeller 19 and off-centred propeller 20,33 , HE 3 20,34 , A 315 17 or Rushton turbine 17 ) as well as for two impellers on a common shaft 22,[35][36][37] .…”

“…Distributions of the heat transfer coefficient along the whole height of the cylindrical wall of the agitated vessel, obtained by means of both thermal and electrochemical methods, were approximated using the following equation (12) In Eq. (12), the value of exponent A is 0.67 for turbulent range of the fluid flow (10 4 < Re < 9 · 10 4 >), and A is 0.58 for the transitional range of the flow Tables 1 and 2.…”

“…On the basis of the equations given in Tables 1 and 2 Comparison of three different configurations of two high-speed impellers on a common shaft, i.e., RT -RT 25 , CD 6 -RT 22 and A 315 -RT, shows that the type of lower impeller (RT, CD 6 or A 315) has decisive effect on the intensity of the heat transfer Ta b l e 1 -Functions Cf 1 f 2 in Eq. (12) for gasliquid systems agitated using two impellers on a common shaft (A 315 (lower) -RT (upper)); turbulent range of the fluid flow (10 4…”

“…Problems of heat transfer in agitated vessels, including theoretical backgrounds, methods of experiments and computations, as well as obtained results have been considered in detail in the following monographs [1][2][3] and papers [4][5][6] . The results of the mean heat transfer coefficient have been given in literature for different agitated liquids, for example: viscous fluids 7-10 , non-Newtonian fluids [10][11][12][13][14] and others [15][16] . The measurements of the local heat transfer coefficient have been also carried out for liquid [17][18][19][20][21] , gas-liquid [21][22][23][24][25][26] , solid-liquid 27 and gas-solid-liquid 28 systems.…”

Liquid‐Solid Mass Transfer Behavior of a Stirred‐Tank Reactor with a Fixed Bed at Its Bottom

“…Considering the drawbacks of slurry reactors, such as catalyst attrition due to collision of the particles with themselves or with the rotating impeller, the low rate of mass transfer between the particles and the solution due to the low slip velocity 1 which tend to reduce the reactor productivity, the possible overflow of catalyst particles outside the reactor in case of continuous operation, erosion of the impeller blades 2, and the labor involved in separating the final product from the catalyst particle, other modes of fixing the catalyst inside the reactor were suggested. The liquid‐solid mass and heat transfer behaviors of the walls of a rectangular and cylindrical agitated vessel where the solid catalyst can be fixed was studied by different authors 3–10. The disadvantages of using the agitated vessel wall as a catalyst support is the limited area of the vessel wall and hence the low reactor productivity.…”