Fig.1

Schematic diagram of film cooling

Fig.2

Diagram of Ra

Fig.3

Diagram of Rz

Fig.4

Schematic diagram of random roughnessgeneration method

Fig.5

Wall surface with random roughness

Fig.6

Roughness height frequency distribution

Fig.7

Experimental system

Fig.8

Structure diagram of the film hole

Fig. 9

Photos of experimental model

Table 1

Structure parameters of film hole

Table 2

Roughness information of test model

Fig.10

Calibration curves of PSP

Table 3

Experimental error

Fig.11

Schematic diagram of the computationaldomain model

Fig.12

Diagram of an unstructured grid

Fig.13

Comparison of film cooling effectiveness of experimental tests and numerical simulations at BR=1.0

Fig.14

Contour of film cooling effectiveness with different roughness at BR=1.0

Fig.15

Effect of roughness on spanwise-averaged film cooling effectiveness at BR=1.0

Fig.16

Contour of film cooling effectiveness with different roughness at BR=2.0

Fig.17

Effect of roughness on spanwise-averaged film cooling effectiveness at BR=2.0

Fig.18

Contour of film cooling effectiveness with different roughness at BR=3.0

Fig.19

Effect of roughness on spanwise-averaged film cooling effectiveness at BR=3.0

Fig.20

Schematic diagram of vortex core development of downstream of the hole at BR=1.0

Fig.21

Velocity ratio contour in X direction for smooth and rough cases at BR=1.0

Fig.22

Velocity ratio contour in Y direction for smooth and rough cases at BR=1.0

Fig.23

Velocity vector distribution at the section of X/D=5.0 for BR = 1.0

Fig.24

Velocity ratio contour in Z direction for smooth and rough cases at BR=1.0

Fig.25

Velocity ratio contour in Y direction for smooth and rough cases at BR=2.0

Fig.26

Velocity vector distribution at the section of X/D=5.0 for BR = 2.0

Fig.27

Velocity ratio contour in Y direction for smooth and rough cases at BR=3.0

Fig.28

Velocity vector distribution at the section of X/D=5.0 for BR = 3.0

Fig.29

Contour of dimensionless temperature field of downstream of the film hole at BR=1.0

Fig.30

Contour of dimensionless temperature field of downstream of the film hole at BR=2.0

Fig.31

Contour of dimensionless temperature field of downstream of the film hole at BR=3.0