# Presentation: 528533

## Engine Nacelle Halon Replacement

## PRESENTATION CONTENTS

- REVIEW EQUIVALENCE DATA TO DATE
- DISCUSS PROGRESS REGARDING OBSERVED OVER-PRESSURES
- DISCUSS STATUS

## REVIEWING EQUIVALENCE DATA TO DATE

| Agent | Ventilation configuration | Fire Threat | Equivalent Concentration (%v/v)
{FIXED DURATION/OBSOLETE VALUES IN BRACES} |
| --- | --- | --- | --- |
| HFC-125 | High | JP8 spray | 17.5 {16.9} |
|  |  | JP8 pool | 7.6 {9.6} |
|  | Low | OIL spray | 16.4 (a) {15.8} |
|  |  | JP8 pool | 8.1 (a) {not determined} |
| CF3I
 | High | JP8 spray | 5.6 {5.8} |
|  |  | JP8 pool | Incomplete |
|  | Low | OIL spray | 7.2 (a,b) {7.2} |
|  |  | JP8 pool | Incomplete |
| (a) Bracketing method used to find mass equivalent |  |  |  |
| (b) Partial result, JP8 verification incomplete as of November 2005 |  |  |  |

## REVIEWING EQUIVALENCE DATA TO DATE

| Agent | Fuel | Peak, Critical or Design Concentration (%v/v) | REFERENCE |
| --- | --- | --- | --- |
| CF3I | PROPANE | 6.5 (p) | NFPA 2001, TABLE A-3-4.3 |
|  | JP8 SPRAY | 3.2 (c) | NIST SP890, V.2, TBL 10, p.115 |
|  | JP8 POOL | 6.8 (c) | NIST SP890, V.2, TBL 10, p.115 |
|  | OIL | 7.2 (d) | FAATC; none; work in progress... |
| HFC-125 | METHANE | 14.7 (p) | NFPA 2001, TABLE A-3-4.3 |
|  | PROPANE | 15.7 (p) | NFPA 2001, TABLE A-3-4.3 |
|  | PROPANE | 12.6 (p) | NIST SP890, V.2, FIG. 41, p.78 |
|  | JP8 SPRAY | 8.7 (c) | NIST SP890, V.2, TBL 10, p.115 |
|  | JP8 POOL | 12 (c) | NIST SP890, V.2, TBL 10, p.115 |
|  | JP8 SPRAY, LoVent | 25.4 (d) | AFRL-VA-WP-TR-1999-3068 |
|  | JP8 SPRAY, HiVent | 18.2 (d) | AFRL-VA-WP-TR-1999-3068 |
|  | JP8 | 17.5 (d) | FAATC; none; work in progress... |

- OTHER REPORTED or CALCULATED CONCENTRATIONS

## OVER-PRESSURE BEHAVIOR – BRIEF OVERVIEW

- IN 2004, TWO HALON REPLACEMENT CANDIDATES WERE OBSERVED TO PRODUCE OVER-PRESSURE PHENOMENA SUBSEQUENT TO REIGNITION WITHIN THE TEST FIXTURE FLOW PATH
- 2-BTP
- HFC-125
- HFC-125 & 2-BTP APPEARED TO ACT AS A FUEL IN SOME INSTANCES
- THE PHENOMENA WAS NOT 100% RELIABLE
- INVESTIGATION REQUIRED DUE TO FREQUENT OCCURRENCE
- OUTCOMES
- 2-BTP WITHDRAWN FROM CONSIDERATION
- ENVIRONMENTAL BEHAVIORS FOR HFC-125 DURING OVER-PRESSURE EVENTS WILL BE RECORDED IN NEAR-TERM TESTING TO PERMIT FUTURE DECISION-MAKING ACTIVITY

## OVER-PRESSURE BEHAVIOR – SCHEMATIC ORIENTATION

- RETURN

## OVER-PRESSURE BEHAVIOR – DUCT INTERFACE IMAGE

## OVER-PRESSURE BEHAVIOR – ACTIVITIES/PLANS TO DATE

- INSTRUMENTATION IS INSTALLED IN TEST FIXTURE & RED DUCT TO CAPTURE ENVIRONMENTAL BEHAVIORS DURING OVER-PRESSURE EVENTS
- 4 THERMOCOUPLES TO MONITOR TEMPERATURES IN RED DUCT
- 2 PRESSURE TRANSDUCERS TO RECORD STATIC PRESSURE
- 4 PHOTOCONDUCTIVE PHOTODIODES TO DETECT FLAME
- DUCT INTERFACE CAN BE ISOLATED FROM TEST BAY
- MINIMIZED THE IMPACT ON THE VENTILATION STREAM ASSOCIATED WITH DUCT INTERFACE ISOLATION
- PERFORMING ANALYTICAL EVALUATIONS OF THE DUCT INTERFACE
- BERNOULLI VELOCITY MEASUREMENTS
- 1ST LAW OF THERMODYNAMICS
- WILL RECORD ENVIRONMENTAL BEHAVIORS NEAR-TERM
- FIRE TESTING WITH NO AGENT, HALON 1301, & HFC-125
- OIL & JP8 (??) SPRAY FIRES
- DUCT INTERFACE OPEN & CLOSED

## OVER-PRESSURE –TELEMETRY PLACEMENT

## OVER-PRESSURE –TELEMETRY BEHAVIORS/OPEN DUCT INTERFACE

## OVER-PRESSURE –TELEMETRY BEHAVIORS/CLOSED DUCT INTERFACE

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

- RECORD STATIC PRESSURE IN RED DUCT AT 2 LOCATIONS
- 21 INCHES FROM INLET & 7 INCHES OFF DUCT WALL (21/7)
- 16 INCHES FROM INLET & 4 INCHES OFF DUCT WALL (16/4)
- ALL FLOWS WERE THE SAME TEMPERATURE; NON-COMBUSTING
- WORKED WITH STREAM LINES FROM TEST BAY INTO RED DUCT; SMOKE TRAIL OBSERVATIONS INDICATED :
- 21/7 WAS IN THE FLUCTUATION BETWEEN THE TEST BAY EDUCTION FLOW & THE TEST SECTION EJECTA
- 16/4 WAS IN THE TEST BAY EDUCTION FLOW SOLELY
- VELOCITIES (mass flows identified in parentheses are based on an assumption that speed is an average value for the annular surface area of the duct inlet where test bay air is entering; i.e. Q=AV; A=0.31 m^2)
- 21/7 :
- T_bay= 13°C, V = 3 m/s (mdot  1.1 kg/s)
- T_bay= 26°C, V = 2.9 m/s (mdot  1.1 kg/s)
-  16/4 : T_bay= 26°C, V = 3.3 m/s (mdot  1.2 kg/s)

- BERNOULLI VELOCITY ANALYSIS

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

- BERNOULLI VELOCITY ANALYSIS

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

- CONTAINED DUCT INTERFACE WITHIN A CONTROL VOLUME (CV)
- NON-COMBUSTING FLOW CONDITIONS
- ESTIMATING MASS FLOW FROM THE TEST BAY INTO RED DUCT
- THE PROBLEM IS UNDER-SPECIFIED
- THE CV WAS “MODELED” FOR VARIABLE INPUTS TO OBSERVE BEHAVIOR OVER A RANGE OF CONDITIONS
- HEAT TRANSFER TO THE BAY ASSUMED NEGLIGIBLE
- WORK = 0
- MASS FLOW FROM THE TEST SECTION IS REASONABLY SIMILAR ACROSS THE AMBIENT CONDITIONS TO TREAT AS A CONSTANT VALUE (1 lbm/s +/- 0.1 lbm/s; 0.45 kg/s +/- 0.05 kg/s)

- 1ST LAW OF THERMODYNAMICS

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

- 1ST LAW OF THERMODYNAMICS

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

- 1ST LAW OF THERMODYNAMICS

## OVER-PRESSURE BEHAVIOR – ANALYTICAL EVALUATION

- 1ST LAW OF THERMODYNAMICS

- TEST BAY = 29°C

- JUMP TO TEST
- FIXTURE SCHEMATIC

## OVER-PRESSURE BEHAVIOR – SUMMATION TO DATE

- TEST FIXTURE IS READY FOR TESTING IN OPEN & CLOSED DUCT INTEFACE CONFIGURATIONS
- ANALYSIS OF VENTILATION AT DUCT INTERFACE NEARING COMPLETION
- SPEEDS FOR RED DUCT & TEST BAY FLOWS HAVE NEGLIGIBLE IMPACT ON CALCULATIONS FOR TEST BAY MASS FLOWS
- ONLY WHEN AIR TEMPERATURE DIFFERS BETWEEN TEST SECTION & TEST BAY
- NEGLIGIBLE IMPACT ILLUSTRATED BY CALCULATED CURVES IN THE REASONABLE REGION OF BULK TEMPERATURE FOR THE RED DUCT FLOW (150-200°F/65-93°C)
- THE GREATEST SENSITIVITY TO THE FLOW SPEEDS EXISTS WHEN THE 3 MASS FLOWS ARE THE SAME TEMPERATURE
_**ESTIMATING**_ 1 kg/s OR LESS ENTERING RED DUCT FROM THE TEST BAY VIA THE INTERFACE
- FUEL/AIR RATIOS TO BE CALCULATED

## CURRENT STATUS

- NEED TO COMPLETE :
- HFC-125 OVER-PRESSURE CHARACTERIZATION
- WORKING ON FUEL-AIR RATIO INFORMATION FOR JP8, OIL, & HYDRAULIC FLUID
- TEST PLAN REQUIRES FINALIZATION
- CF3I EQUIVALENCE TESTING
- JP8 POOL, HIGH & LOW VENTILATION
- JP8 SPRAY, LOW VENTILATION
- COLD-SOAK HFC-125 PROOF (FIRE) TESTS
- WRITE/PUBLISH REPORT & MPSE
- WILL CONSOLODATE WORDS FORMING MPSE & PASS AROUND TO TASK GROUP FOR COMMENT
- MPSE TO BE APPENDIX MATERIAL IN FINAL REPORT
- REPORT BODY TO DESCRIBE HISTORY & LESSONS LEARNED
- DRAFT REPORT DUE SEP 2006