Showing papers in "Experimental Thermal and Fluid Science in 1998"

TL;DR: In this article, the authors compared the heat transfer and pressure drop coefficients for a plain, microfin, and twisted-tape insert-tubes in a single shell-and-tube heat exchanger.

TL;DR: In this article, the volumetric heat transfer coefficients between cellular ceramics and a stream of air were measured using the single-blow transient experimental technique in conjunction with an inverse analysis.

TL;DR: In this paper, the authors compared spray cooling and liquid jet and spray impingement cooling in the non-boiling regime and found that spray cooling can provide the same heat transfer coefficient as jets at a substantially lower mass flux.

TL;DR: In this paper, the authors compared the model proposed by Abramzon and Sirignano with a model using the film concept in natural convection and forced convection initiated by this method.

TL;DR: In this paper, the authors used the Lorentz forces to modify the boundary layer around a circular cylinder in cross flow, which can be used to suppress the von Karman vortex.

TL;DR: In this paper, a high speed camera with 30×-magnification allowed detailed observation of the evaporation process in the tunnels and of the vapor bubbles emerging from the pores.

TL;DR: In this article, the authors used a high speed video camera at 30×magnification to measure bubble dynamics data (bubble diameter, bubble frequency and nucleation site density) on a tubular surface composed of an integral-fin tube.

TL;DR: In this article, the effects of thermophysical properties and geometrical parameters on the droplet and jet flow patterns are described, and measurements of departure-site spacing for several fluids over a wide range of liquid flow rates, tube sizes and tube spacing.

TL;DR: In this paper, the authors investigated secondary flow patterns, pressure drop and heat transfer in rib-roughened rectangular channels, where ribs are attached to the wide channel walls in order to set up swirling motions.

TL;DR: In this article, a single circular jet impinging onto a flat ground board was carried out, where the velocity, normal and shear stress of the wall-joint were measured using hot-wire anemometry.

TL;DR: In this article, the nucleation probability of supercooled water inside cylindrical capsules with or without nucleators during a cold storage process was investigated by performing a number of experiments.

TL;DR: In this article, a straight cylindrical supersonic exhaust diffusers (SED) using cold nitrogen and hot rocket exhaust gases as driving fluids were used to evaluate the effects of the ratios of the SED area to rocket nozzle throat area (Ad/At), SED areas to rocket exhaust manifold exit area, SED length to its diameter (L/D), and specific heat ratio of the driving gases (k) on the minimum starting pressure ratio, (Po/Pa)st, of SED.

TL;DR: In this article, three samples of micro-encapsulated thermochromic liquid crystals with different active temperature ranges were calibrated using a hue-based color decomposition system and a dimensionless temperature was defined that collapsed data from all three samples to a single calibration curve.

TL;DR: In this article, the nucleate boiling heat transfer coefficients were tried to correlate with the equilibrium and dynamic surface tension of the aqueous surfactant solutions, and the results reveal that neither equilibrium nor dynamic surface tensor can successfully explain the boiling phenomena.

TL;DR: In this article, a round flame from a flame-working torch burner was impinged onto a water-cooled metal disk (d b =135 mm) that was segmented into six concentric calorimetric rings.

TL;DR: In this paper, local heat transfer coefficients on the outer surface of tubes in shell-and-tube heat exchangers with staggered tube arrangement are visualized and determined from mass transfer measurements.

TL;DR: In this article, the authors evaluate four different approaches and their theoretical background for determining the local bulk mean temperature and the sensible local heat transfer coefficient using a test model of a turbine blade cooling passage with delta-wing shaped vortex generators mounted on one of the passage walls.

TL;DR: In this paper, the results of experiments on evaporative cooling of water falling freely from one horizontal tube to the next one below it are presented in the same vertical plane, and an empirical equation for calculating the evaporative water cooling is recommended.

TL;DR: In this article, the effect of tumble on integral time scale is negligible, while the integral length scale increases by tumble, and the results show that tumble causes turbulence intensity to increase considerably during the compression stroke and its distribution to be homogeneous.

TL;DR: In this article, a model was developed to predict the pressure drop for flow through an annular packed bed of spheres at random distribution, with a corrected flow velocity, using Ergun's equation.

TL;DR: In this paper, the authors describe a methodology used for designing an experimental model of a two-dimensional louvered fin geometry, scaled up by a factor of 20, that allows for flowfield measurements.

TL;DR: The wide variation in correlations available in the literature for predicting water evaporation rates in a moving air stream necessitated a new investigation to determine which correlations can be considered reliable as mentioned in this paper.

TL;DR: In this article, the behavior of the turbulent boundary layer on a flat plate in a relaminarization process with flow acceleration due to a convergence of the sectional area is experimentally investigated.

TL;DR: In this paper, measurements of flow disturbances in the downstream region of modeled stenoses in a rigid tube, with upstream pulsatile flow are reported, based on the tube diameter and the time-averaged value of upstream centerline velocity.

TL;DR: In this article, the authors present the initiation of a measuring technique with oscillating change of temperature in a non-permeated packed bed of fine-grained material for determining the effective thermal conductivity of a magnesium hydride bed.

TL;DR: In this paper, a two-component laser Doppler velocimeter was employed to measure the flow properties of a confined, isothermal, swirling flowfield in an axisymmetric sudden expansion research combustor.

TL;DR: In this article, the authors considered the control of wake instabilities in the flow of an electrically conducting fluid around a circular cylinder by means of external magnetic fields and presented curves of neutral 2-D stability in the (Re, N )-parameter plane separating steady and periodic flow regimes.

TL;DR: In this paper, the flow field of a coaxial jet configuration having inner to outer diameter ratio Di/Do≅0.5 is studied for two values of the velocity ratio, i.e., Ui/Uo=0.30 and i.a.67, both with a 5 mm thick and with a sharp inner duct wall.

TL;DR: In this paper, the local heat transfer characteristics of a horizontal circular straight tube with a bellmouth inlet were determined experimentally over a flow Reynolds number range of 1500-27,000.

TL;DR: In this article, the effects of particle-to-particle collisions on the characteristics of the particle motion in a vertical downward flowing sudden expansion flow were investigated experimentally and computationally.