Computational Analysis of Flow performance in a C-shape Subsonic Diffuser

In the present investigation the distribution of mean velocity, static pressure and total pressure are experimentally studied on a C-shape diffuser of 40° angle of turn with an area ratio of 1.278 and centerline length was chosen as three times of inlet diameter. The experimental results then were numerically validated with the help of Fluent and then a series of parametric investigations are conducted with same centre line length and inlet diameter but with different area ratios varying from 1.25 to 3.5. The measurements were taken at Reynolds number 2.25 x 10 based on inlet diameter and mass average inlet velocity. Predicted results of coefficient of mass averaged static pressure recovery (50%) and coefficient of mass averaged total pressure loss (11%) are in good agreement with the experimental results of coefficient of mass averaged static pressure recovery (47%) and coefficient of mass averaged total pressure loss (10%) respectively. Standard k-ε model in Fluent solver was chosen for validation. From the parametric investigation it is observed that for the increase in area ratio static pressure recovery increases sharply upto area ratio 2 after that increment in lesser gradient up to 2.67 and it was maximum at area ratio 2.67. But when area ratio increases from 2.67 to 3.5, pressure recovery decreases steadily. The coefficient of total pressure loss almost remains constant with the change in area ratio and angle of turn for similar inlet conditions. KeywordsC-shape diffuser, Five-hole probe, Fluent solver and k-ε model.