ASTM E637 is a standard test method used to calculate stagnation enthalpy in aerodynamic simulation devices (such as plasma arc jets). It combines heat transfer theory with experimental measurements of stagnation-point heat transfer and stagnation pressure to provide consistent data for thermal protection and ablation computations. This test method calculates the stagnation enthalpy from experimental observations of stagnation-point heat transfer and stagnation pressure using heat transfer theory. The values expressed in SI units should be considered the standard.
ASTM E637 Calculation of Stagnation Enthalpy from Heat Transfer Theory and Experimental Measurements of Stagnation-Point Heat Transfer and Pressure
What is ASTM E637?
What is the Scope of ASTM E637?
ASTM E637 provides a standard method for computing an aerodynamic simulation device’s stagnation enthalpy using heat transfer theory and measured stagnation-point heat transfer and pressure. For ablation calculations, the stagnation enthalpy acquired using this test method provides a consistent set of data, including heat transfer and stagnation pressure.
ASTM E637 Testing Procedure
The equation calculates the stagnation enthalpy with the required constants for the Mach number, shape factor, and test gas.
ASTM E637 Analysis Results and Interpretation
q √ R/Pt2 = Ki (He – Hw)
Where q is stagnation-point heat transfer rate, W/m2 (or Btu/ft2·s), Pt2 is model stagnation pressure, Pa (or atm.), R is hemispherical nose radius, m (or ft.), He is stagnation enthalpy, J/kg (or Btu/lb.)
Updated on August 24, 2026
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