The Internal Aerodynamics of Truck-Cargo Containers for Trace-Explosive Sampling
Open Access
- Author:
- Madalis, Matthew
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 03, 2008
- Committee Members:
- Gary Stuart Settles, Thesis Advisor/Co-Advisor
- Keywords:
- sampling
Trace-explosive
detection - Abstract:
- This thesis examines the efficiency of trace-explosive sampling applied to truck-cargo containers, specifically 53-foot van-bodied trailers. By applying a fluid-dynamics perspective to examine current trace-explosive sampling techniques, sampling time can be minimized while providing an increased efficiency. The goal is to sample the trailer's inner airspace without opening its doors. Commercial trailers are first characterized by length, body style, and shipping environment. Further comparisons include door styles, ventilation characteristics inside the trailer, and contrasts between new and used trailers. Full-scale tests are performed to provide insight to the quantity and nature of air leakage between a trailer and its surroundings. Construction of a scale model allows for further testing in a laboratory setting. Qualitative flow-visualization is then conducted to reveal the airflow patterns within the model during both empty and full-container scenarios. Lastly, trace-explosive experiments are performed using minute quantities of RDX vapor released at various locations throughout the scale model. Full-scale testing confirmed that truck trailers have the ability to exchange air with their surroundings when subjected to a pressure differential - a key element to effective trace-explosive sampling and detection. Flow visualization showed that an adequate flow field exists within the scale model, and that a top-front suction vent location yields no areas lacking fluid flow. This was confirmed by detecting trace amounts of RDX vapor all areas inside the model. Based on the results, recommendations are made for future work, and suggestions are made for the design and implementation of commercial sampling devices.