| OCR Text |
Show ^ where m = primary (jet) mass flow m_ = secondary mass flow a r ' = equivalent nozzle radius o ^ C~* ' = mass concentration of the nozzle fluid in the jet of combustible mixture after complete mixing P = nozzle fluid density Pf = density of the fluid after complete mixing (flame) This approach of Thring-Newby which allows for the temperature effect of combustion, by using the equivalent nozzle radius, r ' , is not generally applicable if r '/L >• 0.05 owing to excessive distortion in the nozzle region. .^^ A further similarity parameter for enclosed jets developed by Becker is similar to that of Craya-Curtet, the main difference being that the Craya-Curtet parameter, m, lies between zero and infinity, whereas the Becker throttle factor is between zero and 1. Becker has shown that the Craya-Curtet parameter, m, is in fact a function of the ratio of kinematic to dynamic mean velocities, u,/u,, and that the pattern of a confined turbulent je1? differs profoundly from that of a free jet. In 4his derivation, Becker (5) treated the enclosed jet as a point source, and simplified the relationships for the kinematic and dynamic mean velocities respectively in the following formulae. -10- \J |
