A multipassage internal cooling test model with a 180deg U-bend at the hub was investigated. The flow is radially inward at the inlet passage while it is radially outward at the trailing edge passage. The aspect ratio (AR) of the inlet passage is 2:1 (AR=2) while the trailing edge passage is wedge-shaped with side wall slot ejections. The squared ribs with P/e=8, e/Dh=0.1, =45deg, were configured on both leading surface (LE) and trailing surface (TR) along the inlet passage, and also at the inner half of the trailing edge passage. Three rows of cylinder-shaped pin fins with a diameter of 3mm were placed at both LE and TR at the outer half of the trailing edge passage. For without turning vane case, heat transfer on LE at hub turn region is increased by rotation while it is decreased on the TR. The presence of turning vane reduces the effect of rotation on hub turn portion. The combination of ribs, pin-fin array, and mass loss of cooling air through side wall slot ejection results in the heat transfer coefficient gradually decreased along the trailing edge passage. Correlation between regional heat transfer coefficients and rotation numbers is presented for with and without turning vane cases, and with channel orientation angle at 90deg and 45deg.