Submerged jets in short cylindrical flow vessels

Abstract

Liquid-into-liquid jets in short cylindrical vessels have been investigated under conditions of uniform flow by using an aqueous blue tracer solution in conjunction with tránsparent cylindrical tanks. The vessels had diameters D of 3, 6, 12 and 24in., length-to-diameter ratios L/D of 1, 2 and 3 and inlet diameters d between ¼ and 1 in. Reynolds numbers in the inlet tube, Re_i, ranged between 100 and 28,000. Four main types of jet were observed: \[ \begin{array}{@{}l@{\qquad}l@{\quad}l@{}} & \hbox{dissipated-laminar jets} & (Re_i < 300\;\hbox{approx}.);\\ & \hbox{fully laminar jets} & (300 < Re_i < 1000\;\hbox{approx}.);\\ & \hbox{semi-turbulent jets} & (1000 < Re_i < 3000\;\hbox{approx}.);\\ \hbox{and} & \hbox{fully turbulent jets} & (Re_i > 3000). \end{array} \]The laminar length a of sub-turbulent jets was investigated and correlated with Re_i and the geometric parameters by the equation \[ a/d = 9.97 \times 10^7 Re_i^{-2.46}(D/d)^{-0.48} (L/d)^{0.74}. \]