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ASTM E422-99

(Test Method)

Standard Test Method for Measuring Heat Flux Using a Water-Cooled Calorimeter

Standard Test Method for Measuring Heat Flux Using a Water-Cooled Calorimeter

SCOPE
1.1 This test method covers the measurement of a steady heat flux to a given water-cooled surface by means of a system energy balance.
1.2 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
09-Oct-1999
ICS
17.200.10 - Heat. Calorimetry
Technical Committee
E21 - Space Simulation and Applications of Space Technology
Drafting Committee
E21.08 - Thermal Protection
Current Stage
Ref Project

Relations

Replaced By
ASTM E422-05 - Standard Test Method for Measuring Heat Flux Using a Water-Cooled Calorimeter
Effective Date
15-Sep-2005
Referred By
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
Effective Date
10-Oct-1999
Referred By
ASTM E458-08(2020) - Standard Test Method for Heat of Ablation
Effective Date
10-Oct-1999
Referred By
ASTM E598-08(2020) - Standard Test Method for Measuring Extreme Heat-Transfer Rates from High-Energy Environments Using a Transient, Null-Point Calorimeter
Effective Date
10-Oct-1999
Referred By
ASTM E457-08(2020) - Standard Test Method for Measuring Heat-Transfer Rate Using a Thermal Capacitance (Slug) Calorimeter
Effective Date
10-Oct-1999

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ASTM E422-99 - Standard Test Method for Measuring Heat Flux Using a Water-Cooled CalorimeterASTM E422-99 - Standard Test Method for Measuring Heat Flux Using a Water-Cooled Calorimeter
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ASTM E422-99 - Standard Test Method for Measuring Heat Flux Using a Water-Cooled Calorimeter
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E422–99
Standard Test Method for
Measuring Heat Flux Using a Water-Cooled Calorimeter
This standard is issued under the fixed designation E422; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope state of the boundary layer are outside the scope of this test
method. It should be noted that recombination effects at low
1.1 This test method covers the measurement of a steady
pressurescancauseseriousdiscrepanciesinheatfluxmeasure-
heat flux to a given water-cooled surface by means of a system
ments (such as discussed in Ref (1)) depending upon the
energy balance.
surface material on the calorimeter.
1.2 This standard does not purport to address all of the
3.3 For the particular control volume cited, the energy
safety concerns, if any, associated with its use. It is the
balance can be written as follows:
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
E 5 @mC ~DT 2DT !#/A (1)
CAL p 0 1
bility of regulatory limitations prior to use.
where:
−2
2. Referenced Documents E 5 energy flux transferred to calorimeter face, W·m
CAL
−1
m 5 mass flow rate of coolant water, kg·s
2.1 ASTM Standards:
−1 −1
C 5 water specific heat, J·kg ·K ,
p
E235 Specification for Thermocouples, Sheathed, Type K,
DT 5 T — T calorimeter water bulk temperature rise
2 0 0 0
2 1
for Nuclear or for Other High-Reliability Applications
during operation, K,
DT 5 T — T 5calorimeter water apparent bulk tem-
1 2 1
3. Summary of Test Method
perature rise before operation, K,
3.1 A measure of the heat flux to a given water-cooled
T 5 water exhaust bulk temperature during operation,
surface is based upon the following measurements: (1)the
K,
water mass flow rate and (2)the temperature rise of coolant
T 5 water inlet bulk temperature during operation, K,
water. The heat flux is determined numerically by multiplying
T 5 water exhaust bulk temperature before operation,
the water coolant flow rate by the specific heat and rise in
K,
temperature of the water and dividing this value by the surface
T 5 water inlet bulk temperature before operation, K,
area across which heat has been transferred.
and
3.2 The apparatus for measuring heat flux by the energy-
A 5 sensing surface area of calorimeter, m .
balance technique is illustrated schematically in Fig. 1. It is a
3.4 An examination of Eq 1 shows that to obtain a value of
typical constant-flow water calorimeter used to measure stag-
the energy transferred to the calorimeter, measurements must
nation region heat flux to a flat-faced specimen. Other calo-
be made of the water coolant flow rate, the temperature rise of
rimeter shapes can also be easily used. The heat flux is
the coolant, and the surface area across which heat is trans-
measured using the central circular sensing area, shown in Fig.
ferred. With regard to the latter quantity it is assumed that the
1. The water-cooled annular guard ring serves the purpose of
surface area to which heat is transferred is well defined. As is
preventing heat transfer to the sides of the calorimeter and
indicatedinFig.1,thedesignofthecalorimeterissuchthatthe
establishes flat-plate flow. An energy balance on the system
heat transfer area is confined by design to the front or directly
(the centrally located calorimeter in Fig. 1) requires that the
heated surface. To minimize side heating or side heat losses, a
energy crossing the sensing surface (A, in Fig. 1) of the
water-cooled guard ring or shroud is utilized and is separated
calorimeter be equated to the energy absorbed by the calorim-
physicallyfromthecalorimeterbymeansofanairgapandlow
eter cooling water. Interpretation of the data obtained is not
conductivity bushing such as nylon. The air gap is recom-
within the scope of this discussion; consequently, such effects
mended to be no more than 0.5 mm on the radius. Thus, if
as recombination efficiency of the surface and thermochemical
severe pressure variations exist across the face of the calorim-
eter,sideheatingcausedbyflowintoandoutoftheairgapwill
be minimized. Also, since the water-cooled calorimeter and
This test method is under the jurisdiction ofASTM Committee E-21 on Space
guard ring operate at low surface temperatures (usually lower
Simulation andApplications of SpaceTechnology and is the direct responsibility of
Subcommittee E21.08 on Thermal Protection.
Current edition approved Oct. 10, 1999. Published February 2000. Originally
published as E422–71. Last previous edition E422–83(1994). Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
Annual Book of ASTM Standards, Vol 14.03. this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E422
FIG. 1 Steady-State Water-Cooled Calorimeter.
than 100°C) heat losses across the gap by radiant interchange water-cooled calorimeters be used (rather than one large unit).
are negligible and consequently no special calorimeter surface These shall be located across the heated surface such that a
gap finishes are necessary. Depending upon the size of the heat-flux distribution can be described. With this, a more
calorimeter surface, large variations in heat flux may exist detailed heat-flux measurement can be applied to the specimen
across the face of the calorimeter. Consequently, the measured test and more information can be deduced from the test.
heat flux represents an average heat flux over the surface area
5. Apparatus
of the water-cooled calorimeter. The water-cooled calorimeter
can be used to measure heat-flux levels over a range from 10
5.1 General—The apparatus shall consist of a water-cooled
2 2
kW/m to 60 MW/m .
calorimeter and the necessary instrumentation to measure the
heat transferred to the calorimeter.Although the recommended
4. Significance and Use
instrumentation accuracies are state-of-the-art values, more
4.1 The purpose of this test method is to measure the heat rugged and higher accuracy instrumentation may be required
fluxtoawater-cooledsurfaceforpurposesofcalibrationofthe for high pressure and high heat-flux applications.Anumber of
thermal environment into which test specimens are placed for materials can be used to fabricate the calorimeter, but OFHC
evaluation. If the calorimeter and holder size, shape, and (oxygen free high conductivity) copper is often preferred
surface finish are identical to that of the test specimen, the because of its superior thermal properties.
measured heat flux to the calorimeter is presumed to be the 5.2 Coolant Flow Measurement—The water flow rate to
sameasthattothesample’sheatedsurface.Themeasuredheat each component of the calorimeter shall be chosen to cool the
flux is one of the important parameters for correlating the apparatus adequately and to ensure accurately measurable rise
behavior of materials. inwatertemperature.Theerrorinwaterflowratemeasurement
4.2 The water-cooled calorimeter is one of several calorim- shall be not more than 62%. Suitable equipment that can be
eterconceptsusedtomeasureheatflux.Theprimedrawbackis used is listed in Ref (2) and includes turbine flowmeters,
its long response time, that is, the time required to achieve variableareaflowmeters,etc.Caremustbeexercisedintheuse
steady-stateoperation.Tocalculateenergyaddedtothecoolant of all these devices. In particular, it is recommended that
water, accurate measurements of the rise in coolant tempera- appropriate filters be placed in all water inlet lines to prevent
ture are needed, all energy losses should be minimized, and particles or unnecessary deposits from being carried to the
steady-state conditions must exist both in the thermal environ- water-coolingpassages,pipe,andmeterwalls.Waterflowrates
ment and fluid flow of the calorimeter. and pressure shall be adjusted to ensure that no bubbles are
4.3 Regardless of the source of energy input to the water- formed (no boiling). If practical, the water flowmeters shall be
cooled calorimeter surface (radiative
...

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5.1 The purpose of this test method is to measure the net heat flux to a water-cooled surface for purposes of calibration of the thermal environment into which test specimens are placed for evaluation. The measured net heat flux is one of the important parameters for correlating the behavior of materials. If the calorimeter and holder size, shape, and surface finish are identical to that of the test specimen, the measured net heat flux to the calorimeter is presumed to be the same as that to the sample's heated surface. If the calorimeter configuration (holder size, shape, finish, etc.) is not identical to that of the test specimen, then the measurement results may need to be modified to account for those differences. See Appendix X1.  
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Standard Test Method for Measuring Extreme Heat-Transfer Rates from High-Energy Environments Using a Transient, Null-Point Calorimeter

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5.1 The purpose of this test method is to measure extremely high heat-transfer rates to a body immersed in either a static environment or in a high velocity fluid stream. This is usually accomplished while preserving the structural integrity of the measurement device for multiple exposures during the measurement period. Heat-transfer rates ranging up to 2.84 × 102 MW/m2 (2.5 × 104 Btu/ft2-sec) (7) have been measured using null-point calorimeters. Use of copper null-point calorimeters provides a measuring system with good response time and maximum run time to sensor burnout (or ablation). Null-point calorimeters are normally made with sensor body diameters of 2.36 mm (0.093 in.) press-fitted into the nose of an axisymmetric model.  
5.2 Sources of error involving the null-point calorimeter in high heat-flux measurement applications are extensively discussed in Refs (3-7). In particular, it has been shown both analytically and experimentally that the thickness of the copper above the null-point cavity is critical. If the thickness is too great, the time response of the instrument will not be fast enough to pick up important flow characteristics. On the other hand, if the thickness is too small, the null-point calorimeter will indicate significantly larger (and time dependent) values than the input or incident heat flux. Therefore, all null-point calorimeters should be experimentally checked for proper time response and calibration before they are used. Although a calibration apparatus is not very difficult or expensive to fabricate, there is only one known system presently in existence (6 and 7). The design of null-point calorimeters can be accomplished from the data in this documentation. However, fabrication of these sensors is a difficult task. Since there is not presently a significant market for null-point calorimeters, commercial sources of these sensors are few. Fabrication details are generally regarded as proprietary information. Some users have developed me...
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1.1 This test method covers the measurement of the heat-transfer rate or the heat flux to the surface of a solid body (test sample) using the measured transient temperature rise of a thermocouple located at the null point of a calorimeter that is installed in the body and is configured to simulate a semi-infinite solid. By definition the null point is a unique position on the axial centerline of a disturbed body which experiences the same transient temperature history as that on the surface of a solid body in the absence of the physical disturbance (hole) for the same heat-flux input.  
1.2 Null-point calorimeters have been used to measure high convective or radiant heat-transfer rates to bodies immersed in both flowing and static environments of air, nitrogen, carbon dioxide, helium, hydrogen, and mixtures of these and other gases. Flow velocities have ranged from zero (static) through subsonic to hypersonic, total flow enthalpies from 1.16 to greater than 4.65 × 101 MJ/kg (5 × 10 2 to greater than 2 × 104 Btu/lb.), and body pressures from 105 to greater than 1.5 × 107 Pa (atmospheric to greater than 1.5 × 102 atm). Measured heat-transfer rates have ranged from 5.68 to 2.84 × 102 MW/m2 (5 × 102 to 2.5 × 104 Btu/ft2-sec).  
1.3 The most common use of null-point calorimeters is to measure heat-transfer rates at the stagnation point of a solid body that is immersed in a high pressure, high enthalpy flowing gas stream, with the body axis usually oriented parallel to the flow axis (zero angle-of-attack). Use of null-point calorimeters at off-stagnation point locations and for angle-of-attack testing may pose special problems of calorimeter design and data interpretation.  
1.4 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 appli...

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ASTM E458-08(2020)(Test Method)
Standard Test Method for Heat of Ablation

SIGNIFICANCE AND USE
4.1 General—The heat of ablation provides a measure of the ability of a material to serve as a heat protection element in a severe thermal environment. The parameter is a function of both the material and the environment to which it is subjected. It is therefore required that laboratory measurements of heat of ablation simulate the service environment as closely as possible. Some of the parameters affecting the heat of ablation are pressure, gas composition, heat transfer rate, mode of heat transfer, and gas enthalpy. As laboratory duplication of all parameters is usually difficult, the user of the data should consider the differences between the service and the test environments. Screening tests of various materials under simulated use conditions may be quite valuable even if all the service environmental parameters are not available. These tests are useful in material selection studies, materials development work, and many other areas.  
4.2 Steady-State Conditions—The nature of the definition of heat of ablation requires steady-state conditions. Variances from steady-state may be required in certain circumstances; however, it must be realized that transient phenomena make the values obtained functions of the test duration and therefore make material comparisons difficult.  
4.2.1 Temperature Requirements—In a steady-state condition, the temperature propagation into the material will move at the same velocity as the gas-ablation surface interface. A constant distance is maintained between the ablation surface and the isotherm representing the temperature front. Under steady-state ablation the mass loss and length change are linearly related.
   where:
  t  =  test time, s,   ρo  =  virgin material density, kg/m3,   δL  =   change in length or ablation depth, m,   ρc  =   char density, kg/m3, and   δc  =   char depth, m.  This relationship may be used to verify the existence of steady-state ablation in the tests of charring ablators.  
4.2.2 Exposure T...
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1.1 This test method covers determination of the heat of ablation of materials subjected to thermal environments requiring the use of ablation as an energy dissipation process. Three concepts of the parameter are described and defined: cold wall, effective, and thermochemical heat of ablation.  
1.2 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.  
1.3 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.

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ASTM E3057-19(Test Method)
Standard Test Method for Measuring Heat Flux Using Directional Flame Thermometers with Advanced Data Analysis Techniques

SIGNIFICANCE AND USE
5.1 Need for Heat Flux Measurements:  
5.1.1 Independent measurements of temperature and heat flux support the development and validation of engineering models of fires and other high environments, such as furnaces. For tests of fire protection materials and structural assemblies, temperature and heat flux are necessary to fully specify the boundary conditions, also known as the thermal exposure. Temperature measurements alone cannot provide a complete set of boundary conditions.  
5.1.2 Temperature is a scalar variable and a primary variable. Heat Flux is a vector quantity, and it is a derived variable. As a result, they should be measured separately just as current and voltage are in electrical systems. For steady-state or quasi-steady state conditions, analysis basically uses a thermal analog of Ohm's Law. The thermal circuit uses the temperature difference instead of voltage drop, the heat flux in place of the current and thermal resistance in place of electrical resistance. As with electrical systems, the thermal performance is not fully specified without knowing at least two of these three parameters (temperature drop, heat flux, or thermal resistance). For dynamic thermal experiments like fires or fire safety tests, the electrical capacitance is replaced by the volumetric heat capacity.  
5.1.3 The net heat flux, which is measured by a DFT, is likely different than the heat flux into the test item of interest because of different surface temperatures. An alternative measurement is the total cold wall heat flux which is measured by water-cooled Gardon or S-B gauges. The incident radiative flux can be estimated from either measurement by use of an energy balance [Keltner, 2007 and 2008 (16, 17)]. The convective flux can be estimated from gas temperatures and the convective heat transfer coefficient, h [Janssens, 2007 (18)]. Assuming the sensor is physically close to the test item of interest; one can use the incident radiative and convective fluxes from the...
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1.1 This test method describes the continuous measurement of the hemispherical heat flux to one or both surfaces of an uncooled sensor called a “Directional Flame Thermometer” (DFT).  
1.2 DFTs consist of two heavily oxidized, Inconel 600 plates with mineral insulated, metal-sheathed (MIMS) thermocouples (TCs, type K) attached to the unexposed faces and a layer of ceramic fiber insulation placed between the plates.  
1.3 Post-test calculations of the net heat flux can be made using several methods. The most accurate method uses an inverse heat conduction code. Nonlinear inverse heat conduction analysis uses a thermal model of the DFT with temperature dependent thermal properties along with the two plate temperature measurement histories. The code provides transient heat flux on both exposed faces, temperature histories within the DFT as well as statistical information on the quality of the analysis.  
1.4 A second method uses a transient energy balance on the DFT sensing surface and insulation, which uses the same temperature measurements as in the inverse calculations to estimate the net heat flux.  
1.5 A third method uses Inverse Filter Functions (IFFs) to provide a near real time estimate of the net flux. The heat flux history for the “front face” (either surface exposed to the heat source) of a DFT can be calculated in real-time using a convolution type of digital filter algorithm.  
1.6 Although developed for use in fires and fire safety testing, this measurement method is quite broad in potential fields of application because of the size of the DFTs and their construction. It has been used to measure heat flux levels above 300 kW/m2 in high temperature environments, up to about 1250 °C, which is the generally accepted upper limit of Type K or N thermocouples.  
1.7 The transient response of the DFTs is limited by the response of the MIMS TCs. The larger the thermocouple the slower the transient response. Res...

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ASTM E2684-17(Test Method)
Standard Test Method for Measuring Heat Flux Using Surface-Mounted One-Dimensional Flat Gages

SIGNIFICANCE AND USE
5.1 This test method will provide guidance for the measurement of the net heat flux to or from a surface location. To determine the radiant energy component the emissivity or absorptivity of the gage surface coating is required and should be matched with the surrounding surface. The potential physical and thermal disruptions of the surface due to the presence of the gage should be minimized and characterized. For the case of convection and low source temperature radiation to or from the surface it is important to consider how the presence of the gage alters the surface heat flux. The desired quantity is usually the heat flux at the surface location without the presence of the gage.  
5.1.1 Temperature limitations are determined by the gage material properties and the method of application to the surface. The range of heat flux that can be measured and the time response are limited by the gage design and construction details. Measurements from 10 W/m2 to above 100 kW/m2 are easily obtained with current sensors. Time constants as low as 10 ms are possible, while thicker sensors may have response times greater than 1 s. It is important to choose the sensor style and characteristics to match the range and time response of the required application.  
5.2 The measured heat flux is based on one-dimensional analysis with a uniform heat flux over the surface of the gage surface. Because of the thermal disruption caused by the placement of the gage on the surface, this may not be true. Wesley (3) and Baba et al. (4) have analyzed the effect of the gage on the thermal field and heat transfer within the surface substrate and determined that the one-dimensional assumption is valid when:
   where:
  ks  =   the thermal conductivity of the substrate material,    R   =  the effective radius of the gage,    δ  =  the combined thickness, and     k  =  the effective thermal conductivity of the gage and adhesive layers.    
5.3 Measurements of convective heat flux are part...
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1.1 This test method describes the measurement of the net heat flux normal to a surface using flat gages mounted onto the surface. Conduction heat flux is not the focus of this standard. Conduction applications related to insulation materials are covered by Test Method C518 and Practices C1041 and C1046. The sensors covered by this test method all use a measurement of the temperature difference between two parallel planes normal to the surface to determine the heat that is exchanged to or from the surface in keeping with Fourier’s Law. The gages operate by the same principles for heat transfer in either direction.  
1.2 This test method is quite broad in its field of application, size and construction. Different sensor types are described in detail in later sections as examples of the general method for measuring heat flux from the temperature gradient normal to a surface (1).2 Applications include both radiation and convection heat transfer. The gages have broad application from aerospace to biomedical engineering with measurements ranging form 0.01 to 50 kW/m 2. The gages are usually square or rectangular and vary in size from 1 mm to 10 cm or more on a side. The thicknesses range from 0.05 to 3 mm.  
1.3 The values stated in SI units are to be regarded as the standard. The values stated in parentheses are provided for information only.  
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.  
1.5 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...

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