Left

**1. Description of the example**

A hypersonic vehicle is a vehicle that flies with a Mach number greater than 5 (that is, it is capable of achieving hypersonic long-range flight in the atmosphere and across the atmosphere). Sustained hypersonic flight leads to severe aerodynamic heating phenomena, which poses a major challenge to the thermal protection design of hypersonic vehicles.

It is well known that the design of lightweight structures and thermal protection systems for hypersonic vehicles depends largely on accurate and reliable predictions of aerothermal loads, structural temperatures and their gradients, as well as structural deformations and stresses. The physical phenomenon of significant interaction between the external aerodynamic flow field and the internal temperature field of the aircraft structure through the fluid-solid interface is often referred to as conjugate heat transfer (CHT).

Therefore, accurate prediction of CHT problems in hypersonic airflow is of great significance for structural material selection and optimal design of thermal protection systems.

Based on Dimaxer2023R2, this example performs CHT simulation calculations on a typical cylindrical leading edge model, and verifies the function of Dimaxer2023R2 to solve the conjugate heat transfer problem.

**2. Calculation status**

2.1 Computational Model

Figure 1: Calculating geometry dimensions

2.2 Computing Networks

Using a full hexahedral mesh, the mesh at the fluid-solid interface is co-noded.

Figure 2: Partial enlarged view of the overall grid and the fluid-solid interface

The number and quality of the grids can be checked in Dimaxer, as shown in Figure 3:

Figure 3: Grid mass distribution

2.3 Physical parameters

The ideal gas model is used for fluids, and Sutherland's law is used for viscosity.

The physical property parameters of the solid side are shown in the following table:

2.4 Boundary Conditions

The boundary conditions used in this study are shown in Figure 4:

Figure 4: Boundary condition definition

**3. Calculation results**

3.1 Flow field data

Along the direction of the incoming flow, a straight line of the flow field passing through the standing line, and the change law of pressure and temperature on the line with time is as follows:

00:04

Comparing the calculated data in the figure with the calculated data in the literature, the calculated value of Dimaxer is basically consistent with the calculated value of the literature.

3.2 Interface surface pressure distribution

The surface pressure distribution at the interface is shown in Figure 5:

Figure 5: Comparison of the circumferential distribution of pressure at the fluid-solid interface

Any circumferential line is taken on the surface, and the normalized pressure value is compared with the test value with the standing pressure, as shown in Figure 6:

Figure 6: Comparison of the circumferential distribution of pressure at the fluid-solid interface

As can be seen from the figure, the interface pressure value calculated by Dimaxer is in good agreement with the test value.

The heat flux at the interface is also addressed, which is the main concern of the hypersonic CHT problem, and the heat flux calculated by Dimaxer is in good agreement with the experimental values.

Figure 7: Comparison of the circumferential distribution of heat flux at the fluid-solid interface

**4. Computing efficiency**

In this example, 800,000 grids are used to solve with 4th order precision, about 51 million solving points, and four 4090 GPU cards are used, and each flow cycle takes 2.1 GPU hours.

**5. Summary**

In this example, the CHT calculation of Dimxer2023R2 on the hypersonic cylindrical leading edge model is introduced, and the calculation results prove that Dimxer2023R2 is applicable and efficient to such problems.

Reference：

[1] Kamali S , Mavriplis D J , Anderson E M .Development and Validation of a High-Fidelity Aero-Thermo-Elastic Analysis Capability[C]//AIAA Scitech 2020 Forum.2020.DOI:10.2514/6.2020-1449.

Right

Rankyee 粤ICP备2023060583号