The exit flow fields of a circular convergent nozzle with three lobed mixers were measured at atmospheric pressure and two flow conditions

to study the impact of velocity ratio on the mixing performance.An annular mixer was also tested for comparison.The results show that the curves of pressure uniformity with the velocity ratio have "convex" shapes.Their peak values appear at velocity ratio 1 under cold conditions

and at velocity ratio 0 68 under hot conditions.The two velocity ratio values are directly proportional to the square root of temperature ratio under cold and hot conditions.Contrary

the curves of pressure loss coefficient with the velocity ratio have "concave" shapes.The velocity ratio values at the valley points of the curves are dependent on the configuration of the mixers

and are both less than those at the peak points of the pressure uniformity curves under cold and hot conditions.The temperature uniformity decreases with the increase of velocity ratio in the test range.The correlation is linear when the velocity ratioslie 0 2～0 7

and then it changes smoothly as the velocity ratio is greater than 0 7.