6. Combustor diffuser nozzle sections

A dual mode scramjet configuration, as presented in Figure 30, in addition to having a fore-section consisting of a forebody, inlet, isolator sections; also has an aft-section consisting of a combustor, diffuser and nozzle sections. Whilst the focus of this chapter has been on the design of the fore-section, a brief discussion on the design of the aft-section and its integration is warranted for the sake of completion in the design of the dual mode scramjet.

Design of the aft-section focuses on four fundamental design sections; a transition section, a combustor section, a diffuser section and a nozzle section, Figures 31 and 32. The transition section, as implied in the name, is designed to prepare the

flow before it enters the combustor. This section takes the flow leaving the isolator duct and guides it towards combustor. The primary design goal is to ensure that the flow entering the combustor is as organized as possible. The combustion section is where fuel is added, mixed and burned. The diffuser section is used to help control the combustion process as the scramjet operates across its dual mode, that is, switching from ramjet mode to scramjet mode. The nozzle section is used to accel-

A completed scramjet flow-path can now be obtained with the assembly of both

the forebody-inlet-isolator and combustor-nozzle sections. Two samples are presented in Figures 33 and 34. Figure 33 presents a scramjet that has a square combustor configuration and Figure 34, a circular combustor configuration. Referring back to Figure 2(c), one can observe that a variety of geometries can be

erate the exhaust gases as the flow leaves the dual mode scramjet.

7. Scramjet flow-path

Illustration of the transition-combustor-nozzle element.

Inversely Designed Scramjet Flow-Path DOI: http://dx.doi.org/10.5772/intechopen.85697

Figure 32.

Figure 33.

Figure 34.

71

4-pts scramjet with square combustor C-sections.

4-pts scramjet with circular combustor C-sections.

Figure 30.

A dual mode ramjet-to-scramjet concept [1].

Figure 31.

2D-3D geometric construction from prescribes isolator cross-section and aerodynamic inputs [1].

Inversely Designed Scramjet Flow-Path DOI: http://dx.doi.org/10.5772/intechopen.85697

A similar process was implemented with AVUS and 2-D slices of flow-field data are extracted and presented in Figures 25–29. On examining these 2-D slices of 3-D data, it is observed that the stream tube is processing the flow in an organized consistent manner that is aligned with its design. Of note are Figures 27–29. Figure 27 examines the z-component of the velocity, and indicated that there is very little cross-flow. Arguable, this is an Euler analysis, however it is worth pointing out that the stream tube 2-D design process holds. This is further supported by Figures 28 and 29 which presents data on the Mach and pressure

A dual mode scramjet configuration, as presented in Figure 30, in addition to having a fore-section consisting of a forebody, inlet, isolator sections; also has an aft-section consisting of a combustor, diffuser and nozzle sections. Whilst the focus of this chapter has been on the design of the fore-section, a brief discussion on the design of the aft-section and its integration is warranted for the sake of completion

Design of the aft-section focuses on four fundamental design sections; a transition section, a combustor section, a diffuser section and a nozzle section, Figures 31 and 32. The transition section, as implied in the name, is designed to prepare the

2D-3D geometric construction from prescribes isolator cross-section and aerodynamic inputs [1].

distribution at the isolator exit.

6. Combustor diffuser nozzle sections

Hypersonic Vehicles - Past, Present and Future Developments

in the design of the dual mode scramjet.

A dual mode ramjet-to-scramjet concept [1].

Figure 30.

Figure 31.

70

Figure 32. Illustration of the transition-combustor-nozzle element.

flow before it enters the combustor. This section takes the flow leaving the isolator duct and guides it towards combustor. The primary design goal is to ensure that the flow entering the combustor is as organized as possible. The combustion section is where fuel is added, mixed and burned. The diffuser section is used to help control the combustion process as the scramjet operates across its dual mode, that is, switching from ramjet mode to scramjet mode. The nozzle section is used to accelerate the exhaust gases as the flow leaves the dual mode scramjet.
