Numerical Analysis for Smoke Spread in an Aircraft Hangar

Essam E Khalil,Hatem Haridy ,Eslam Said Abdelghany Ahmed ,Ahmed Ashraf Mohamed

doi:10.1051/e3sconf/201911101090

Abstract

Smoke is one of the most dangerous factors in aircraft hangar in case of fire. As it causes reduce in visibility and deaths due to high temperature or toxicity also prevents applying evacuation plan for workers. This study present numerical analysis for improving traditional system of ventilation system to manage smoke produced due to push-back vehicle on fire at hangar. By studying effect of changing extraction and supply rates, the number of extraction and supply fans, and the arrangement of extraction and supply fans on the visibility, temperature and air velocity at human level to insure not to exceed limits stated by NFPA 130[1] to apply evacuation plan for workers. The study is performed using Fire dynamic simulator to simulate 16 case studies in the hangar of airports in Brandenburg. The hangar has the outer dimensions of 83.40 m width and 77.60 m depth and thus an inner area of approx. 6,472 m2. The hangar has a medium interior height of approximately 18.20 m. The results show that using extraction fans with rate (ACH) double the supply rate for the traditional ventilation system gives very good results in controlling the smoke. As well as, decreasing the number of supply fans will make the smoke spread rate inside the hangar lower, which helps to control the smoke spread of fire in less time.

Highlights

Aircraft hangars, by their very nature, pose a unique challenge for fire safety engineers
With the fast development of computer technology, computational fluid dynamics (CFD) simulation has been becoming an important means of engineering calculations of fluid motion and ventilation
Visibility, temperature and velocity contours are simulated at human level (1.8 m) as the suitable condition for applying the evacuation plan is that the visibility should not be less than 10 m, temperature not higher than 60 C and air speed less than 11 m/s according to NFPA 130 [1]

Summary

1.Introduction

By their very nature, pose a unique challenge for fire safety engineers. For fire safety design to be effective, a number of issues must first be considered These include fire source, heat transfer, fire detection and alarm, human behavior, smoke movement, toxicity and pollution. Natural Ventilation; depends on convection currents, wind, and other natural air movement to allow contaminated atmosphere to flow out of a structure. Positive-pressure ventilation uses fans to introduce clean air into a structure and push the contaminated atmosphere out. A series of jet fans are distributed beneath the ceiling, produce air movement from the air inlet openings towards pre-designated extract points, transferring smoke and fumes with it. The computational domain used in the case study has the same dimensions of the actual hangar as shown in figure 1. Simulation case studies as well as four fire scenarios are shown in table 1

Governing Equations

Results And Discussion

4.Concluding Remarks

5.References