1. ME 475/675 Introduction to Combustion Lecture 31 Laminar flame speed and thickness dependence on unburned temperature, pressure, fuel and dilution, Ex. 8.2,

2. Announcements HW 13 Due Monday, November 9, 2015 Midterm 2 Review Monday, Nov. 9, 2015 Tutorial: Thursday, November 12, 2015, 5-7 pm, SEM 257 Exam: Friday, November 13, 2015 PE 104, 8 to 9:30 (or 9:45?) AM Project In groups of two, construct a backpacking stove Materials will be supplied in lab Determine how long it takes and how much fuel is required to boil water Form your group by Monday, November 9 Inform TA: Hasibul Alam hasibul.alam.bd@gmail.comhasibul.alam.bd@gmail.com http://wolfweb.unr.edu/homepage/greiner/teaching/MECH.475.675.Combustion/TermProjectAssignment.pdf

3. Pressure and temperature dependence of S L and

4. Dependence on Fuel Type

5. Flame Speed Correlations for Selected Fuels

6. Example 8.3, p. 286

7. Graduate Research topic using combustion Large Fire Heat transfer Dependence of Fire Time of Concern on Package Location for a 1 PWR Transport Package Paper

8. Dependence of Fire Time of Concern on Package Location for a 1 PWR Transport Package Ketan Mittal Research Assistant University of Nevada, Reno Miles Greiner Professor of Mechanical Engineering University of Nevada, Reno Funded by the US Nuclear Regulatory Commission, Contract NRC-HQ- 12 -P- 02-0200 Packaging and Transportation of Radioactive Materials August 20, 2013 –San Francisco, California Ahti Suo-Anttila Computational Engineering Analysis LLC Albuquerque, New Mexico

9. Motivation Consider a package designed to transport one used nuclear fuel assembly in proximity to a long-lasting, 12-m diameter jet fuel fire If the package is centered over the pool, how long will it take before the fuel’s cladding reaches its possible burst temperature, 750°C? How far must the package be from the pool’s center so that its cladding will not reach this temperature, even for an infinitely-long-lasting fire? (Safe distance)

10. Package Response Finite Element Model  Models fuel block, steel-lead-steel construction surrounded by water tank  Inside package, heat generation within the fuel, conduction and surface-to-surface radiation heat transfer

11. Normal Conditions of Transport Temperatures  Fuel heat generation, Solar heat flux  Natural convection and radiation heat transfer to 38 ° C environment  External surface temperature, hottest at center

12. Internal Temperature

13. Comparison to Previous studies

14. Container Analysis Fire Environment Simulations

15. Max Cladding Temperature vs time for package Centered over 12-m Pool Simulations were performed for a range of modeling parameters Calculated fire time of concern for the cladding t c (when the cladding reaches 750°C) is between 11.8 and 13.3 hours

16. Dependence on Package Location The fire time of concern for the cladding increases as the distance between the package and fuel centers increases For S x > 6.4 m (package over the pool edge) the cladding temperature never reaches its burst condition. This work helps risk analysts determine which actual fires have the potential to affect safety and require further study

17. Time of Concern versus Package Position

19. Flame Quenching, Mixture Flammability, Ignition

20. Cold Wall Quenching Quenching distance d Smallest dimension d that allows flame to pass Experimentally determined by shutting off flow of a premixed stabilized flame d tube = (1.2 to 1.5) d tube Could we design and build an experiment to observe this using different sized screens? d d

21. Simplified Quenching Analysis for a slot b=2 b>2

22. Quenching will take place when b=2 b>2

24. Example 8.4, page 290