Peter S. Veloo

CONVECTIVE HEAT TRANSFER COEFFICIENT IN COMPARTMENT FIRES

Heat transfer to compartment surfaces was measured in fully developed fire experiments. The experiments involved scaled compartments ranging from 1/8th to 3/8th with full-scale height of 2.54 m. Gas temperatures reached 1000°C, and total surface heat flux could reach 200 kW/m2, with convection accounting for 25% of the total. A combination of thermopile heat flux gage, metal plate sensor, and gas and wall thermocouples was used to separate the convective and radiative components. The convective heat transfer coefficients were resolved experimentally. Convective heat transfer coefficient was correlated against temperature rise within the compartment for both flaming and after extinction phases.

Comparative Evaluation of Global Combustion Properties of Alternative Jet Fuels

Global high temperature and low temperature combustion properties of one conventional jet fuel (JP-8) and four alternative jet fuels are examined. The global combustion characteristics of these five fuels were hypothesized a priori based on a set of four property targets used in the formulation of surrogate jet fuels in recent studies by the authors. The high temperature combustion properties were evaluated by measuring two near-limit flame behaviors: the radical index derived from extinction limits of diffusion flames, and the critical flame initiation radius in outwardly propagating premixed flames. Two fundamental flame measurements reveal that Shell SPK exhibits the strongest high temperature reactivity, whereas Sasol IPK exhibits the lowest reactivity among the tested fuels. The relative low to intermediate temperature reactivities of these five jet fuels were compared by performing oxidation reactivity experiments in a high pressure flow reactor. The oxidation reactivity profiles demonstrated that Sasol IPK has no low temperature reactivity. The remaining jet fuels demonstrated extensive reactivity between 500 to 750 K. Of interest, despite sharing similar derived cetane numbers, Shell SPK shows a more pronounced low temperature reactivity compared to HRJ Camelina. Consequently, the results in this study indicate that the proposed four property targets can be used to predict the global combustion properties of petroleum derived jet fuels and perhaps for blends with alternative jet fuels up to 50%, but further refinements appear to be needed to precisely predict the temperature dependencies of global combustion properties of alternative jet fuels containing no aromatics.

Characterization of Global Combustion Properties with Simple Fuel Property Measurements for Alternative Jet Fuels

Global combustion characteristics of one conventional jet fuel (JP-8) and four non-petroleum alternative jet fuels (Shell Synthetic Paraffinic Kerosene (SPK), Sasol Iso-Paraffinic Kerosene (IPK), Hydrotreated Renewable Jet (HRJ Camelina and HRJ Tallow)) are experimentally examined. The ranking of the fully pre-vaporized global combustion characteristics of these five fuels has been hypothesized