# Presentation: 822639

## HEAT FLUX MEASUREMENT WITH A FOIL-TYPE

**      ****GARDON GAGE SENSOR IN THE RADIANT **
**                            ****PANEL TEST SYSTEM**
-                                                                           **KHANG D. TRAN, Ph.D.**
**                                                                        ****THE MEXMIL COMPANY**
**                                                                  ****SANTA ANA, CALIFORNIA,  USA**

- International Aircraft Materials Fire Test Working Group Meeting, March 2004, Atlantic City, NJ

## FAR 25.856 (a) flammability test requires a heat flux value of 1.5 ± 0.075 Btu/s·ft2 at zero-point location (1.425 - 1.575).

- Calibration data has been recorded and analyzed to confirm
- the compatibility of the test system with the allowed 5% tolerance

## CALIBRATION CURVE FOR RADIANT PANEL SYSTEM

- Controller Setting Temperature : 1165 °F

**Heat Flux**
**(Btu/s.ft****2****)**

**Position**

- Zero Point

-  2 inches

## TEMPERATURE OF RADIANT PANEL CHAMBER AT THE 

**CHAMBER TEMPERATURE (F)**

**TIME (s)**

**TEMPERATURE OF RADIANT PANEL CHAMBER AT THE **
**THERMOCOUPLE 1 LOCATION (11 IN., 2 IN., 11.5 IN.)**

## HEAT FLUX AT ZERO-POINT LOCATION 

**HEAT FLUX AT ZERO-POINT (BTU/S•FT****2****)**

**TIME (S)**

**HEAT FLUX AT ZERO-POINT LOCATION**

**Thermal stability begins**

## CHAMBER TEMPERATURE AND HEAT FLUX CORRELATION

**CHAMBER TEMPERATURE AND HEAT FLUX CORRELATION**

- Thermal stability

## CHAMBER TEMPERATURE AND HEAT FLUX CORRELATION

- (560, 1.5)

**CHAMBER TEMPERATURE AND HEAT FLUX CORRELATION**

**There exists a linear relationship between the chamber temperature (at **
**location of interest (11 in., 2 in., 11.5 in.) and the zero-point heat flux. **

**HEAT FLUX AT ZERO-POINT (BTU/S•FT****2****)**

**CHAMBER TEMPERATURE (F)**

## TEMPERATURE-HEAT FLUX CORRELATION (CEAT LAB)

##       1.5 ± 5 % Btu/s·ft2 (or 1.7 ± 5 % Watts/cm2)

**      ****1.5 ± 5 % Btu/s·ft****2 ****(or 1.7 ± 5 % Watts/cm****2****)**
**= (1.425 - 1.575) Btu/s·ft****2 ****or (1.615 - 1.785) Watts/cm****2****)**

**558.7****	****1.452****	**
**559.0****	****1.452****	**
**559.0****	****1.456****	**
**559.3****	****1.458****	**
**559.2****	****1.454****	**
**558.9****	****1.481****	**
**559.3****	****1.465****	**
**559.6****	****1.486****	**
**559.6****	****1.481****	**
**559.9****	****1.481****	**
**559.7****	****1.479****	**
**559.8****	****1.495****	**

**560.2****	****1.456****	**
**560.6****	****1.481****	**
**560.8****	****1.492****	**
**561.4****	****1.492****	**
**561.4****	****1.474****	**
**561.7****	****1.474****	**
**561.8****	****1.479****	**
**561.7****	****1.477****	**
**561.8****	****1.458****	**
**562.7****	****1.456****	**
**562.7****	****1.486****	**
**562.0****	****1.51**

- There is a variation of about 3 °F (0.054%) of the chamber temperature at the location
- of interest when the heat flux fluctuates in the range of (1.45-1.51) **Btu/s·ft****2 **

**DATA IN 24 SEC.**
**DURATION **
**AFTER**
**THERMAL**
**STABILITY**
**BEGINS**

## CIRCULAR FOIL-TYPE GARDON GAGE HEAT FLUX SENSOR*

- E (Voltage output)

- 

- Copper
- body

- Constantan
- foil

- To

- Ts

- Copper
- wire

- The center to edge temperature
- difference is proportional to the
- heat flux
-                    Q R2
- To - Ts =
-                              4k

-  = thickness of the foil
- R = active radius of the foil
- k = thermal conductivity of
-       the material.

- * T. E. Diller, “Heat Flux”, CRC Press LLC, 2000 and the references cited in this paper

- Besides the heat conduction, both heat
- convection and heat radiation are present at
- least to some extent in virtually all cases. The
- foil-type Gardon gage sensor output is not
- completely correct because of the distortion
- of the temperature profile in the foil from the
- assumed radially symmetric, parabolic profile
- of heat radiation.