US 11,454,566 B2Granted

Parameter similarity method for test simulation conditions of aerodynamic heating environment

AssigneeDalian University of Technology

InventorsDechuan Sun, Ming Lu

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Abstract

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.

A parameter similarity method for test simulation conditions of an aerodynamic heating environment, comprising the following steps:

(1) assuming temperature of a free stream as T¥, free stream Mach number of the free stream as Ma¥ and free stream heat capacity ratio of air as g at flight condition;
calculating recovery temperature
T
r
⁢
1
=
T
¥
(
1
+
r
⁢
g
-
1
2
⁢
Ma
¥
2
)
of the free stream, wherein r is a temperature recovery coefficient which ranges from 0.88 to 0.92;
calculating adiabatic wall enthalpy hr1=∫0Tr1cpdT of the free stream wherein cp is specific heat capacity of air at constant pressure and T represents the temperature;
(2) calculating a first 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;
for a turbulent flow state of a flat surface, obtaining the first convective heat transfer coefficient
a1=0.0296(Re1*)−1/2(Pr1*)−2/3(rv)¥cp
wherein Re1* is a Reynolds number of a free stream at reference temperature;
Pr1* is a Prandtl number of the free stream at reference temperature;
(rv)¥ is a momentum of the free stream;
calculation equations of the first convective heat transfer coefficients of other geometric structural surfaces are slightly different from this, and refer to a relevant aerodynamic heating engineering algorithm;
(3) calculating a cold-wall heat flux according to the first convective heat transfer coefficient obtained in the step (2);
q01=a1(Tr1−T0),
wherein T0 is cold-wall temperature, T0=300K;
(4) calculating a wall surface temperature Tw1 of the material of the flight vehicle structure under the cold-wall heat flux determined in the step (3) by using a method of computational heat transfer;
(5) when an adiabatic wall enthalpy hr2 of a gas flow of a test device is less than the adiabatic wall enthalpy hr1 of the free stream, assuming a first total temperature of an initial gas flow as T2*=Tw1+20K according to the geometry of the test device and the free stream condition, and calculating a second convective heat transfer coefficient α2 on the surface of a test piece in the test by using a method of computational fluid dynamics;
(6) making the surface temperature of the test piece as Tw2=Tw1, and adjusting the recovery temperature of the gas flow in the test device according to the second convective heat transfer coefficient α2 calculated in the step (5);
T
r
⁢
2
=
a
1
a
2
⁢
(
T
r
⁢
1
-
T
w
⁢
1
)
+
T
w
⁢
2
calculating a second total temperature T2*=Tr2/r2 of the gas flow, wherein r2 is a temperature recovery coefficient of the test condition;
substituting T2* into the step (5), repeating the calculation of step (5) to step (6), and conducting a next step until Tr2 and a2 tend to be stable;
(7) determining the cold-wall heat flux of the test condition
q
02
=
a
2
(
T
r
⁢
2
-
T
0
)
a
1
(
T
r
⁢
1
-
T
0
)
⁢
q
01
.

93 more elements

Facts

Application

16/647,432Filed 21 Mar 2019

Priority

CN 201810789945.418 Jul 2018

Published

US 2020/0217749 A19 Jul 2020

Granted

27 Sep 2022

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01M 9/04
Wind tunnels: details
G01M 9/065
Measuring arrangements specially adapted for aerodynamic testing: dealing with flow
G01M 9/02
Aerodynamic testing; Arrangements in or on wind tunnels: wind tunnels
G01M 99/002
Subject matter not provided for in other groups of this subclass: thermal testing

Abstract

Claims1