Aerodynamic Heating Simulation Parameter Similarity Method
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Solution Overview
Problem
Current ground test devices for simulating hypersonic aerodynamic heating environments struggle to accurately replicate flight conditions, particularly when adiabatic wall enthalpy and cold-wall heat flux are not equal, leading to high costs and deviations from actual flight conditions.
Innovation Solution
A parameter similarity method that adjusts test conditions by calculating recovery temperature, convective heat transfer coefficients, and surface temperatures to match cold-wall heat flux and hot-wall heat flux without relying on equal adiabatic wall enthalpy, allowing for wider simulation conditions and more cost-effective testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If arc-heated wind tunnel is used to simulate high enthalpy flight conditions, then simulation accuracy is improved, but test cost increases and test cycle lengthens
Solution Approach 1:
The patent changes the similarity parameters from requiring equal adiabatic wall enthalpy to using equal hot-wall heat flux with corrected cold-wall heat flux. This parameter transformation allows using lower-cost combustion wind tunnels instead of expensive arc-heated wind tunnels, while maintaining simulation accuracy through the correction method.
Solution Approach 2:
The patent enables the use of cheaper combustion wind tunnels with shorter test cycles by replacing the expensive arc-heated wind tunnel. The correction method compensates for the limitations of combustion wind tunnels, making them suitable for high enthalpy simulation without requiring costly arc heating facilities.
2Ease of manufacture
If oxyacetylene ablation test device is used to simulate flight conditions, then test cost is reduced, but simulation accuracy deteriorates due to ignoring adiabatic wall enthalpy effects
Solution Approach 1:
The patent transforms the similarity criterion from adiabatic wall enthalpy equality to hot-wall heat flux equality with cold-wall heat flux correction. This allows oxyacetylene devices to accurately simulate high enthalpy conditions by using the correction method, eliminating the need to consider adiabatic wall enthalpy while maintaining accuracy.
Solution Approach 2:
The patent introduces the hot-wall heat flux as an intermediary parameter that connects the test conditions to flight conditions. By using hot-wall heat flux equality and cold-wall heat flux correction as intermediaries, the patent enables accurate simulation through simpler, lower-cost devices without directly matching adiabatic wall enthalpy.
3Device complexity
If combustion wind tunnel is used for simulation, then adiabatic wall enthalpy is limited to below 4000 kJ/kg, but device complexity and cost are reduced
Solution Approach 1:
The patent changes the similarity parameters to hot-wall heat flux and corrected cold-wall heat flux, which removes the 4000 kJ/kg enthalpy limitation of combustion wind tunnels. This parameter transformation expands the simulation range of combustion wind tunnels to cover high enthalpy conditions that previously required arc-heated wind tunnels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures similarity between ground test and flight parameters, expanding simulation capabilities and reducing the high costs associated with arc-heated wind tunnels, while maintaining accuracy in heat transfer and ablation tests for thermal protection materials.
Implementation Method 1
calculating recovery temperature Tr1 of the free stream, wherein r is a temperature recovery coefficient
Implementation Method 2
calculating a convective heat transfer coefficient a1 of the surface of a flight vehicle structure according to characteristics of the flight vehicle structure and an aerodynamic heating engineering algorithm
Implementation Method 3
The device for ground simulation of the aerodynamic heating environment using heat radiation mainly heats the wall surface of a structural component by radiative heat flux generated by a bank of quartz lamps
Data Source
AI summary
A parameter similarity method for test simulation conditions of an aerodynamic heating environment is disclosed. With respect to the requirement that the adiabatic wall enthalpy and the cold-wall heat flux are equal in the simulation test of the aerodynamic heating environment, a method that can ensure the similarity of ground test parameters and flight parameters without the equal adiabatic wall enthalpy is proposed, and solves the problems of relying on the equal adiabatic wall enthalpy and making it difficult to accurately simulate the real aerodynamic heating environment in the current test simulation method, and provides guarantee for heat transfer and ablation test research of thermal protection/insulation material under the high temperature aerodynamic heating environment. The test conditions are not affected by the value of the adiabatic wall enthalpy. According to the method, most test devices can simulate the aerodynamic heating environment with high enthalpy.