An experimental study of the transient build-up of a methane fire located in an in-line room corridor small scale test facility has been conducted. The data is specifically designed to be used for evaluation and development of transient field models as well as global models which predict these flows. Local temperature and velocity data were taken at the center line of the facility at various axial locations along with flow visualizations using smoke injection techniques. The data are presented in two forms which show the transient development of floor to ceiling profiles as well as the time history at single points. It was found that the data for the first minute after ignition of the methane flame were adequate to characterize conditions when adiabatic walls are assumed. The data of this study show some significant differences from previously published studies.

An experimental and theoretical investigation of the interaction of gaseous thermal radiation with natural convection was made for a laminar methane-air diffusion flame in the lower stagnation region of a horizontal porous cylinder. The exponential wide-hand gas radiation model was employed in this nonhomogeneous (nonuniform in temperature and composition) problem through the use of scaling techniques. Using a numerical scheme, the compressible energy, flow, and species-diffusion equations were solved simultaneously with and without the radiative component. In the experiment, methane was blown uniformly from the surface of the porous cylinder, setting up (upon ignition) a diffusion flame within the free-convection boundary layer. Using a Mach-Zehnder interferometer and a gas chromatograph, temperature and composition measurements were obtained along the stagnation line. Excellent agreement was found between the results based on the nongray wide-band model and the experimental data. Furthermore, it was found that the wide-band model yielded results that were superior to those results that excluded radiation-interaction effects. Thus, this study demonstrates that the exponential wide-band model can be accurately applied to nonhomogeneous combustion situations in order to account for the radiation-convection interactions.

A numerical model for the prediction of unsteady, two dimensional buoyant flows is presented. The model makes use of the full elliptic balance equations for heat, mass, and momentum and allows for full coupling between density and temperature. The model is highly flexible in that it can accomodate variable transport properties and complex boundary conditions. Of particular importance, it is capable of treating surfaces such as a doorway or window across which there can be a free inflow or outflow of fluid to the computational region. The model has been used to predict the time dependent velocity and temperature fields generated by fire in an enclosure or corridor. It has proven successful in predicting the gas velocities and temperatures generated by the fire in the enclosure corridor geometries, the ventilation of the fire through windows or doorways, and the heat transfer rates to the various surfaces involved. In these cases combustion is modeled by volumetric heat sources. The results for two particular cases are presented and comparisons are made with experiment.

Experimental measurements for natural convection mass transfer adjacent to vertical and downward-facing inclined surfaces were performed using an electrochemical technique. The measurements yielded the time average and instantaneous mass transfer rates for the laminar, transition, and turbulent flow regimes along the test surface. The laminar mass transfer measurements were found to agree with both the analytical and experimental results for both the vertical and downward-facing inclined surfaces. The Rayleigh number marking the onset of the transition from laminar flow conditions depended heavily upon the angle of inclination of the test surface. In the turbulent regime the time average local mass transfer coefficient was correlated by the Rayleigh number to 1/3 power.

Natural convection adjacent to horizontal surfaces of circular, square, rectangular, and right triangular planforms has been studied experimentally. Electrochemical techniques were employed involving a fluid with a Schmidt number of about 2200. The results encompass a wide range of Rayleigh numbers thus providing information on both the laminar and the turbulent regimes. The data for all planforms are reduced to a single correlation in the laminar and turbulent regimes using the characteristic length, as recommended by Goldstein, Sparrow, and Jones. L* = A/p, where A is the surface area and p is the surface perimeter. The laminar data for all planforms are correlated by the expression Sh=0.54Ra1/4(2.2×104≤Ra≤8×106) and the data for the turbulent regime are correlated by the expression Sh=0.15Ra1/3(8×106≤1.6×109) Transition is found to occur at about Ra = 8 × 106. The present work thus significantly extends the Rayleigh number range of validity for the use of L* through the 1/4 power laminar regime into the turbulent 1/3 power regime. It also demonstrates the validity of the use of L* to correlate natural convection transfer coefficients for highly unsymmetrical planforms, which heretofore had not been demonstrated. Comparisons to analytical solutions and other experimental heat and mass transfer data are presented.

The stability of laminar flow in a parallel-plate channel having one permeable bounding wall is investigated by means of linear theory. The analysis takes account of the coupling of the disturbance fields in the channel and in the permeable material and of velocity slip at the surface of the permeable wall. Complementary experiments are performed in which the breakdown of the laminar regime in flat rectangular ducts is identified from pressure-drop measurements and from flow visualization studies. The experiments cover the range of slip velocities from 15–30 percent of the mean velocity and, in addition, the case of zero slip (impermeable walls). In the slip range of the experiments, the instability Reynolds number results of both analysis and experiment lie below the corresponding values for the case of the impermeable-walled duct. Furthermore, in this range, the instability Reynolds numbers are rather insensitive to variations in the slip velocity. Quantitative agreement between analysis and experiment was found to be somewhat better in the slip range than for the impermeable-walled duct.

Experiments on natural convection mass transfer adjacent to vertical and upward-facing inclined plates were performed by employing an electrochemical technique. Local measurements were made, yielding both streamwise and spanwise mass transfer distributions. Time-dependent mass transfer rates were measured in the transition and turbulent regimes.

It is demonstrated experimentally that local fluid injection into a turbulent tube flow gives rise to substantial increases in the heat transfer coefficients in the region downstream of the injection station. In the experiments, fluid was injected into a mainstream flow through a ring of discrete holes situated just upstream of an electrically heated test section. Water was the working fluid. The augmentation of the heat transfer coefficients due to injection is found to increase as the ratio of the injected flow to the test section flow increases. The extent of the augmentation is greater for low Reynolds number turbulent flows than for high Reynolds number turbulent flows.

An experimental investigation of the effect of asymmetrical heating on fully developed turbulent heat transfer has been carried out. The test apparatus was a rectangular duct of aspect ratio 5:1. The duct was constructed so that the two long sides of the rectangular cross section could be heated at different preselected rates, while the two short sides were unheated. Two cases of asymmetrical heating were studied: (a) One of the two long sides was heated, while the second was unheated; (b) both of the long sides were heated, with the heating rate at one side being twice that of the other. For the first case, the heat transfer coefficients are lower than those for the symmetrically heated duct. For the second case, the coefficients for the more strongly heated wall are also below the values for symmetrical heating, while the coefficients for the lesser-heated wall are greater than the symmetric heating results. These findings are in qualitative agreement with analytical predictions for the parallel-plate channel. Furthermore, by applying an analytically motivated correlation procedure (reference [10]), it was shown that overall Nusselt number results for asymmetric heating could be brought into virtual coincidence with those for symmetric heating.

The use of computational fluid dynamics (CFD) tools for modelling and analysing process systems has increased in recent years. A campaign has begun to investigate whether it is possible to simulate metering stations that include flow conditioners (FCs) and orifice meters. However, more information and validation are required in several areas before the technique can be fully exploited. This study was initiated prior to the start of full pipe simulation to investigate various grid effects, coordinate arrangements, wall boundary conditions, differencing schemes and turbulence models that can predict more accurate flow values through an orifice. The calculations were carried out in two-dimensional axisymmetric flow. The findings can be used in modelling both FCs and orifice plates.