Fig.1

Main components of DFNSE［25］

Fig.2

Three-dimensional computational model of engine lip for anti-icing using DFNSE

Fig.3

Three-dimensional model of directed flow nozzle

Fig.4

Schematic diagram of contraction-expansion section of annular flow passage of engine lip

Fig.5

Engine lip model using a piccolo tube for anti-icing

Fig.6

Computational boundary conditions for different anti-icing structures

Fig.7

Computational meshes for different anti-icing structures

Fig.8

Model of experimental specimen［30］

Fig.9

Computational model for validation case

Fig.10

Computational mesh for validation case

Table 1

Boundary conditions for validation case

Fig.11

Schematic diagram of axial cross-section of vortex tube

Fig.12

Comparison between numerical simulation and experimental results

Table 2

Computational meshes with different numbers of grids

Table 3

Operating conditions of a typical high-bypass-ratio turbofan engine

Fig.13

Average wall convective heat transfer coefficient of internal flow passage under different numbers of grids

Table 4

Physical properties of solid materials

Fig.14

Calculation results of lip anti-icing related parameters using DFNSE and piccolo tube

Fig.15

Temperature distribution of engine lip outer wall for anti-icing using DFNSE and piccolo tube

Table 5

Geometric parameters of different twist angles in internal flow passage of directed flow nozzle

Fig.16

Schematic diagram of sampling points for engine lip temperature data

Fig.17

Temperature distribution of engine lip surface for anti-icing using DFNSE with different internal flow passage twist angles

Fig.18

Circumferential temperature variation of lip outer skin and inner and outer rings of internal flow passage

Fig.19

Calculation results of anti-icing related parameters for DFNSE with different twist angles in internal flow passage of a directed flow nozzle

Table 6

Geometric parameters of different internal flow passage for directed flow nozzles

Fig.20

Surface temperature distribution of engine lip for different numbers of internal flow passage in directed flow nozzles

Fig.21

Circumferential temperature variation of lip outer skin and inner and outer rings of directed flow nozzles with different numbers of internal flow passage

Fig.22

Outer skin temperature and bleed air pressure of directed flow nozzles with different numbers of internal flow passage

Table 7

Different contraction-expansion ratio parameters of DFNSE annular flow passage

Fig.23

Surface temperature distribution of engine lip with DFNSE anti-icing at different contraction-expansion ratios

Fig.24

Outer skin temperature of engine lip with DFNSE anti-icing at different contraction-expansion ratios

Fig.25

Circumferential temperature variation of engine lip with DFNSE anti-icing at different contraction-expansion ratios

Fig.26

Flow conditions at directed flow nozzles outlet with different contraction-expansion ratios

Fig.27

Pressure distribution in contraction-expansion section of annular flow passage under different contraction-expansion ratios

Fig.28

Pressure of bleed air for DFNSE anti-icing and pressure in low-pressure region of contraction-expansion section at different contraction-expansion ratios

Fig.29

DFNSE and piccolo tube anti-icing heating mass coefficient with different geometric configurations