ASTM E637-22

Standard Test Method for Calculation of Stagnation Enthalpy from Heat Transfer Theory and Experimental Measurements of Stagnation-Point Heat Transfer and Pressure

SIGNIFICANCE AND USE
3.1 The purpose of this test method is to provide a standard calculation of the stagnation enthalpy of an aerodynamic simulation device using the heat transfer theory and measured values of stagnation point heat transfer and pressure. A stagnation enthalpy obtained by this test method gives a consistent set of data, along with heat transfer and stagnation pressure for ablation computations.
SCOPE
1.1 This test method covers the calculation from heat transfer theory of the stagnation enthalpy from experimental measurements of the stagnation-point heat transfer and stagnation pressure.  
1.2 Advantages:  
1.2.1 A value of stagnation enthalpy can be obtained at the location in the stream where the model is tested. This value gives a consistent set of data, along with heat transfer and stagnation pressure, for ablation computations.  
1.2.2 This computation of stagnation enthalpy does not require the measurement of any arc heater parameters.  
1.3 Limitations and Considerations—There are many factors that may contribute to an error using this type of approach to calculate stagnation enthalpy, including:  
1.3.1 Turbulence—The turbulence generated by adding energy to the stream may cause deviation from the laminar equilibrium heat transfer theory.  
1.3.2 Equilibrium, Nonequilibrium, or Frozen State of Gas—The reaction rates and expansions may be such that the gas is far from thermodynamic equilibrium.  
1.3.3 Noncatalytic Effects—The surface recombination rates and the characteristics of the metallic calorimeter may give a heat transfer deviation from the equilibrium theory.  
1.3.4 Free Electric Currents—The arc-heated gas stream may have free electric currents that will contribute to measured experimental heat transfer rates.  
1.3.5 Nonuniform Pressure Profile—A nonuniform pressure profile in the region of the stream at the point of the heat transfer measurement could distort the stagnation point velocity gradient.  
1.3.6 Mach Number Effects—The nondimensional stagnation-point velocity gradient is a function of the Mach number. In addition, the Mach number is a function of enthalpy and pressure such that an iterative process is necessary.  
1.3.7 Model Shape—The nondimensional stagnation-point velocity gradient is a function of model shape.  
1.3.8 Radiation Effects—The hot gas stream may contribute a radiative component to the heat transfer rate.  
1.3.9 Heat Transfer Rate Measurement—An error may be made in the heat transfer measurement (see Method E469 and Test Methods E422, E457, E459, and E511).  
1.3.10 Contamination—The electrode material may be of a large enough percentage of the mass flow rate to contribute to the heat transfer rate measurement.  
1.4 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4.1 Exception—The values given in parentheses are for information only.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jul-2022
• ICS: 17.200.10 - Heat. Calorimetry
• Technical Committee: E21 - Space Simulation and Applications of Space Technology
• Drafting Committee: E21.08 - Thermal Protection

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E637 − 22
Standard Test Method for
Calculation of Stagnation Enthalpy from Heat Transfer
Theory and Experimental Measurements of Stagnation-Point
1
Heat Transfer and Pressure
This standard is issued under the fixed designation E637; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The enthalpy (energy per unit mass) determination in a hot gas aerodynamic simulation device is
a difficult measurement. Even at temperatures that can be measured with thermocouples (1), there are
many corrections to be made at 600 K and above. Methods that are used for temperatures above the
range of thermocouples that give bulk or average enthalpy values are energy balance (see Practice
2
E341), sonic flow (2, 3), and the pressure rise method (4). Local enthalpy values (thus distribution)
may be obtained by using either an energy balance probe (see Method E470), or the spectrometric
technique described in Ref (5).
1. Scope 1.3.3 Noncatalytic Effects—Thesurfacerecombinationrates
and the characteristics of the metallic calorimeter may give a
1.1 This test method covers the calculation from heat
heat transfer deviation from the equilibrium theory.
transfer theory of the stagnation enthalpy from experimental
1.3.4 Free Electric Currents—The arc-heated gas stream
measurements of the stagnation-point heat transfer and stagna-
mayhavefreeelectriccurrentsthatwillcontributetomeasured
tion pressure.
experimental heat transfer rates.
1.2 Advantages:
1.3.5 Nonuniform Pressure Profile—Anonuniform pressure
1.2.1 Avalue of stagnation enthalpy can be obtained at the profile in the region of the stream at the point of the heat
location in the stream where the model is tested. This value transfer measurement could distort the stagnation point veloc-
gives a consistent set of data, along with heat transfer and ity gradient.
stagnation pressure, for ablation computations. 1.3.6 Mach Number Effects—The nondimensional
stagnation-point velocity gradient is a function of the Mach
1.2.2 This computation of stagnation enthalpy does not
number.Inaddition,theMachnumberisafunctionofenthalpy
require the measurement of any arc heater parameters.
and pressure such that an iterative process is necessary.
1.3 Limitations and Considerations—There are many fac-
1.3.7 Model Shape—The nondimensional stagnation-point
tors that may contribute to an error using this type of approach
velocity gradient is a function of model shape.
to calculate stagnation enthalpy, including:
1.3.8 Radiation Effects—The hot gas stream may contribute
1.3.1 Turbulence—The turbulence generated by adding en-
a radiative component to the heat transfer rate.
ergy to the stream may cause deviation from the laminar
1.3.9 Heat Transfer Rate Measurement—An error may be
equilibrium heat transfer theory.
made in the heat transfer measurement (see Method E469 and
1.3.2 Equilibrium, Nonequilibrium, or Frozen State of
Test Methods E422, E457, E459, and E511).
Gas—The reaction rates and expansions may be such that the
1.3.10 Contamination—The electrode material may be of a
gas is far from thermodynamic equilibrium.
large enough percentage of the mass flow rate to contribute to
the heat transfer rate measurement.
1.4 Units—The values stated in SI units are to be regarded
1
This test method is under the jurisdiction of ASTM Committee E21 on Space
asstandard.Nootherunitsofmeasurementareincludedinthis
Simulation andApplications of SpaceTechnology and is the direct responsibility of
standard.
Subcommittee E21.08 on Thermal Protection.
1.4.1 Exception—The values given in parentheses are for
Current edition approved Aug. 1, 2022. Published September 2022. Originally
approvedin1978.Lastpreviouseditionapprovedin2016asE637–05(2016).DOI:
information only.
10.1520/E0637-22.
2
1.5 This standard does not purport to address all of the
The boldface numbers in parentheses refer to the list of references appended to
this method. safety concerns, if any, associated with its use. It is the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E637 − 22
responsibility of the user of this standard to establish appro- lytic theoretical laminar stagnation-point heat transfer rate for
priate safety, health, and environmental practices and deter- a hemispherical body is as follows (6):
mine the applicability of regulatory limita
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E637 − 05 (Reapproved 2016) E637 − 22
Standard Test Method for
Calculation of Stagnation Enthalpy from Heat Transfer
Theory and Experimental Measurements of Stagnation-Point
1
Heat Transfer and Pressure
This standard is issued under the fixed designation E637; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The enthalpy (energy per unit mass) determination in a hot gas aerodynamic simulation device is
a difficult measurement. Even at temperatures that can be measured with thermocouples,
thermocouples (1), there are many corrections to be made at 600 K and above. Methods that are used
for temperatures above the range of thermocouples that give bulk or average enthalpy values are
2
energy balance (see Practice E341), sonic flow (12, 23), and the pressure rise method (34). Local
enthalpy values (thus distribution) may be obtained by using either an energy balance probe (see
Method E470), or the spectrometric technique described in Ref (45).
1. Scope
1.1 This test method covers the calculation from heat transfer theory of the stagnation enthalpy from experimental measurements
of the stagnation-point heat transfer and stagnation pressure.
1.2 Advantages:
1.2.1 A value of stagnation enthalpy can be obtained at the location in the stream where the model is tested. This value gives a
consistent set of data, along with heat transfer and stagnation pressure, for ablation computations.
1.2.2 This computation of stagnation enthalpy does not require the measurement of any arc heater parameters.
1.3 Limitations and Considerations—There are many factors that may contribute to an error using this type of approach to
calculate stagnation enthalpy, including:
1.3.1 Turbulence—The turbulence generated by adding energy to the stream may cause deviation from the laminar equilibrium
heat transfer theory.
1.3.2 Equilibrium, Nonequilibrium, or Frozen State of Gas—The reaction rates and expansions may be such that the gas is far from
thermodynamic equilibrium.
1
This test method is under the jurisdiction of ASTM Committee E21 on Space Simulation and Applications of Space Technology and is the direct responsibility of
Subcommittee E21.08 on Thermal Protection.
Current edition approved April 1, 2016Aug. 1, 2022. Published April 2016September 2022. Originally approved in 1978. Last previous edition approved in 20112016 as
E637 – 05 (2011).(2016). DOI: 10.1520/E0637-05R16.10.1520/E0637-22.
2
The boldface numbers in parentheses refer to the list of references appended to this method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E637 − 22
1.3.3 Noncatalytic Effects—The surface recombination rates and the characteristics of the metallic calorimeter may give a heat
transfer deviation from the equilibrium theory.
1.3.4 Free Electric Currents—The arc-heated gas stream may have free electric currents that will contribute to measured
experimental heat transfer rates.
1.3.5 Nonuniform Pressure Profile—A nonuniform pressure profile in the region of the stream at the point of the heat transfer
measurement could distort the stagnation point velocity gradient.
1.3.6 Mach Number Effects—The nondimensional stagnation-point velocity gradient is a function of the Mach number. In addition,
the Mach number is a function of enthalpy and pressure such that an iterative process is necessary.
1.3.7 Model Shape—The nondimensional stagnation-point velocity gradient is a function of model shape.
1.3.8 Radiation Effects—The hot gas stream may contribute a radiative component to the heat transfer rate.
1.3.9 Heat Transfer Rate Measurement—An error may be made in the heat transfer measurement (see Method E469 and Test
Methods E422, E457, E459, and E511).
1.3.10 Contamination—The electrode material may be of a large enough percentage of the mass flow rate to contribute to the heat
transfer rate measurement.
1.4 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.4.1 Exception—The values given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the respons
...