STRUCTURE OF THE DETACHED GAS–DROPLET FLOW AND HEAT TRANSFER IN AN AXISYMMETRIC CONFUSER

Results of a numerical investigation of the infl uence of a negative longitudinal pressure gradient, arising at an abruptly enlarged cross section of a pipe with an axisymmetric confuser, on the structure of the turbulent gas– droplet fl ow and the heat transfer in the confuser of the pipe are presented. It is shown that a favorable pressure gradient in such a pipe signifi cantly infl uences the characteristics of the two-phase fl ow and the heat transfer in its confuser. An increase in the convergence angle of the confuser in this pipe leads to a decrease in the turbulence of the gas–droplet fl ow in it by more than four times compared to the turbulence of the gas–droplet fl ow downstream of an abruptly enlarged cross section of an analogous pipe with no convergence (φ = 0o ). It was established that the recirculation zone in the gas–droplet fl ow in the confuser is substantially smaller in length (by 30%) and the point at which the heat transfer in it reaches a maximum is shifted somewhat downstream, as compared to those in the gradient-free detached gas–droplet fl ow in the pipe with no convergence, and the coordinate of the maximum heat transfer in the confuser is practically coincident with the coordinate of the attachment of the detached two-phase fl ow in it.
   
Author:  M. A. Pakhomov and V. I. Terekhov
Keywords:  heat and mass transfer, confuser, fl ow separation, abrupt enlargement, numerical simulation
Page:  1473