A detailed two-dimensional transient model has been formulated and numerically solved for concurrent flames over thick and thin solids in low-speed forced flows. The processes of flame growth leading to steady states are numerically simulated. For a thick solid, the steady state is a nongrowing stationary flame with a limiting length. For a thin solid, the steady state is a spreading flame with a constant spread rate and a constant flame length. The reason for a nongrowing limiting flame for the thick solid is the balance between the flame heat feedback and the surface radiative heat loss at the pyrolysis front, as first suggested by Honda and Ronney. The reason for achieving a steady spread for thin solids is the balance between the solid burnout rate and the flame tip advancing rate. Detailed transient flame and thermal profiles are presented to illustrate the different flame growth features between the thick- and thin-solid fuel samples.

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Two solid pyrolysis models are employed in a concurrent-flow flame spread model to compare the flame structure and spreading characteristics. The first is a zeroth-order surface pyrolysis, and the second is a first-order in-depth pyrolysis. Comparisons are made for samples when the spread rate reaches a steady value and the flame reaches a constant length. The computed results show (1) the mass burning rate distributions at the solid surface are qualitatively different near the flame (pyrolysis base region), (2) the first-order pyrolysis model shows that the propagating flame leaves unburnt solid fuel, and (3) the flame length and spread rate dependence on sample thickness are different for the two cases.

BackgroundSkin tear is a common problem encountered in the Emergency Department. If it is not properly managed, it can lead to wound infection, skin necrosis and a need for further surgical intervention and skin grafting. Current management is to cleanse the wound, replace the thin skin flap followed by coverage with a dressing that is inducive for wound healing. Several dressings have been suggested for the coverage of these wounds. But, up to now, there has been no mention of the use of a silver-based hydrofiber dressing in the management of this condition. The objective of this study was to explore the use of a silver-based hydrofiber dressing for the management of paper-thin skin tears. MethodsWe retrospectively reviewed all patients with class I or II skin tears that had undergone management using a silver based hydrofiber dressing between October 2019 till October 2020. Demographic data and medical history was obtained by retrospective chart review. Data that was collected included: age, sex, comorbid illnesses, defect location, defect size, complications, number of times the silver-based hydrofiber dressing was replaced and the number of days required to achieve complete wound healing. ResultsA total of 65 patients were included in the study. There were 39 males and 26 females. There were 28 patients whose age was greater then 85 years old, of which 14 patients were over 90 years old. The mean number of outpatient visits were 2. The mean defect size was 33cm2 (range 1cm x 1cm to 18x10cm). The mean number of days required for total wound healing was 13 days (range 7-21). We did not encounter any patients that required further surgical debridement or split-thickness skin grafting. ConclusionThe use of a silver-based hydrofiber dressing was well tolerated by the elderly population as it provided an easy, efficient, economical and effective form of management of skin tears. We suggest that a silver-based hydrofiber dressing can be used as a first-line treatment method for class I and II skin tears.