Principal Investigator: Albert Ratner
Sponsors & Partners
University of Iowa
About this Project
Brief Project Description & Background
Fuel fires are a significant hazard in many modes of transportation. For aircraft, the experience has been that approximately half of all crash-related fatalities are due to ground fires. For hazardous material transport with tractor trailers, one of the primary requirements and tests is for the container to survive a specified amount of time (typically 30 to 60 minutes) in a fuel fire. In general, fuel fires are a significant threat to both human life and transported freight.
To minimize the likelihood and mitigate the resulting damage of fuel fires, one method is to reduce the ease with which the fuel can be ignited. This must be done in crash scenarios while not affecting normal vehicle and engine operation. Our existing MATC grant has already shown polymer-based mist suppression is feasible in diesel systems. While that work is focused characterizing diesel, diesel surrogate, and polymer-added drop behavior (and comparing these results to existing kerosene data), this effort will produce data describing realistic operating conditions and mapping these to the diesel drop results from the first study. The current work will characterize all 3 shear regimes (low- fuel pumping, medium- accidental fuel release, and high- engine injection) and includes assessment of engine spray conditions so that an accurate time-varying shear stress profile can be measured and then correlated.
The goal of this research is to improve the safety of tractor-trailer and train-based transport. This is directly in line with MATC’s goal “to make fundamental advancements in basic and theoretical research related to improving the safety of and minimizing the risk to the U.S. surface transportation system.” This work is focused on ground-based freight moving systems that utilize diesel as their primary fuel. The research work proposed here is fundamental in nature, that is, the goal is to establish a framework and identify fluid shear-stress regimes that will enable the development of polymer additives that provide mist-control while being otherwise transparent to diesel fuel supply and to engine operation.
The results will include databases for both real engine and lab-scale fluid shear rates and a methodology for translating results between the two. This will then set the guidelines for polymer performance that can be acted upon by polymer chemists. This, along with more detailed database information, creates a path for construction of a polymer that can achieve the desired level of mist suppression while not adversely affecting diesel transportation system operation.
Having found that misting-controlling agents appear to be applicable in reducing the danger posed by fuel fires for diesel-engine-based ground transportation vehicles, this proposal will endeavor to establish the actual fluid shear rates that occur in various phases of the diesel vehicle fuel system and relate these to liquid drop test conditions that are the primary focus of laboratory work. There are 3 key regimes that will be examined, including normal flow and pumping (low shear), accident-induced fuel release (medium shear), and engine injection (high shear). The intent is to establish these values for the various fuel systems and for the range of diesel formulations. These can then be mapped to shear rates that occur in the drop impact process, particularly for diesel surrogates (these are being studied as part of our initial MATC grant). This information then provides the framework for creating testing procedures and clear goal posts for misting-controlling polymer performance. These then serve as the criteria for designing polymers that are effectively transparent to the fuel supply infrastructure and engine operation while still providing the desired fire mitigation benefits during accidents. This research will provide a key step for transforming these polymers from an interesting lab-scale novelty to something where successful candidate polymers can begin in-situ engine-scale testing.
Safety and Human Performance
Technology Transfer Activities
This work will serve to “establish the goal posts” rather than being a more direct attempt at finding the winning solution. The information to be collected in this work is vital, and will be used by both academia and industry to set research directions and evaluate their results. The PI will publish the results and make digested versions available on our group website (as we have with aircraft crash data that we collected for a previous study).