No abstract

No abstract

Herein, experimental and numerical validation studies were conducted on internal channel cooling in which seven jets impinging inside a rotating semi-cylindrical channel. These studies were conducted by considering a Reynolds number of 7,500 for a jet at five rotation speeds (ranging from 0 to 200 rpm). Numerical analysis was performed using the shear stress transport (SST) k–ω turbulence model with a properly analyzed fine mesh containing eight million nodes. A test setup with required instrumentation was developed inhouse for this study. Two temperature measurement techniques, namely thermochromic liquid crystals (TLCs) and thermocouples, were adopted. Further, the target surface temperature contours were precisely analyzed by comparing the TLC temperature measurements with the numerical temperature results. The captured temperature contours indicated points of minimum-temperature regions, which corresponded to the jet impingement regions. By examining the temperature distribution along the axial centerline, a good agreement was established between the numerical results and the experimental measurements. For Reynolds number of 7,500, increasing ration speed from 0 to 250 rpm has reduced the variation in temperature between different jets. The size of inlet port to feeding duct has a strong imapact on jet formation, which led to different mass flow rate across jets. Furthermore, a small deviation between numerical and experimental data can be observed near the end side of the channel owing to the radial and lateral heat transfer losses and outlet flow restriction.

In the present study, the effect of angular velocity on mass fraction per jet is evaluated using three dimensional numerical model. A steady state model with constant wall temperature is used to investigate the performance of seven jets impinging an airfoil leading edge cavity. The numerical simulation is conducted using ANSYSfluent release 19.1. The study analyse the impact of jet location, jet Reynolds number and rotation number on flow behaviour and how they impact cross flow interaction. The results show that the amount of mass fraction depends mainly on channel size, jet size, jet location, rotation number and Reynolds number. The highest mass fraction is found for jets near the flow outlet while the lowest mass fraction is found from the jets in farthest distance from the outlet. Under angular velocity, that mass fraction increases with rotation number for the jet near the outlet due to centrifugal force, while decreases for the jets near the rotation axis. The rotation caused higher maximum temperature at low Reynolds number (7,500 and 10,000) while it produced lower maximum temperature at high Reynolds number (20,000 and 30,000).

No abstract