Showing papers in "Experimental Thermal and Fluid Science in 1991"

TL;DR: Triangular and rectangular longitudinal vortex generators were formed by punching small pieces out of flat plate fins so that they stuck out of the plates and formed an angle (angle of attack) with the main flow direction.

TL;DR: In this paper, the authors used smoke-wire flow visualization technique to gain a deeper physical insight into a regular vortex structure of free and impinging round subsonic jets, with the uniformly distributed smoke filaments providing a cross-sectional view of the jet within the first few diameters.

TL;DR: In this article, a phenomenological model is proposed to explain the mass exchange between neighboring subchannels in rod bundles with different aspect ratios, by means of the model, mass exchange among neighboring sub-channels is explained.

TL;DR: The results obtained in several turbulent shear flows demonstrate that the measurement uncertainty intervals can be made sufficiently small by the employment of three TV cameras and a precise camera calibration procedure.

TL;DR: In this article, an experimental investigation was made into the effects of frost growth on the thermal performance of fin tube heat exchangers with wavy and corrugated fins, and it was found that higher air humidity and fin density lead to more frost growth and higher pressure drops.

TL;DR: The naphthalene sublimation technique is reviewed in detail in detail as discussed by the authors, and the fundamentals on which it relies are discussed, and then its basic characteristics and typical procedures are presented.

TL;DR: In this paper, the authors measured the flow structure and heat transfer of impinging flame jets as well as impinging isothermal jets from two rapid-heating burners, and showed that heat transfer from isothermal and flame jets can be described in the same way with this velocity gradient and a turbulence enhancement factor.

TL;DR: In this paper, a hybrid scheme combining experimental and numerical methods was developed to study heat transfer in the case of a circular jet impinging on a moving metal plate, which was intended to resemble the cooling system in steel rolling.

TL;DR: The surface tension of aqueous polymer solutions of polyacrylamide (PAM), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), and hydroxyethyl celluloses (HEC) was studied over a range of polymer concentrations by using the maximum bubble pressure method at temperatures ranging from 20 to 65°C.

TL;DR: In this paper, the importance of frequency response considerations in the use of thin-film gages for unsteady heat transfer measurements in transient facilities is considered, and methods for evaluating it are proposed.

TL;DR: In this article, a detailed experimental study of the heat transfer in an open isothermal cubic cavity for mixed natural and forced convection is reported, where the main influence of natural convection can be separated, and, using regressional analysis, a general interdependence among Nusselt, Reynolds, and Grashof numbers can be obtained.

TL;DR: In this paper, an analytical technique was developed to spectrally compensate for both of these effects and showed that end-conduction effects were important in θ′ measurements as well as vθ and uθ measurements and that compensated results agreed with data from several previous studies in which end conduction should have been negligible.

TL;DR: In this article, a new apparatus was developed to measure local convection coefficients for heat transfer to an impinging liquid jet, which is unique in that heat fluxes sufficient to induce steady convective boiling were delivered to an area large enough to accomodate local measurements.

TL;DR: In this paper, a viscous oil flowing through a horizontal tube containing a twisted tape was analyzed to understand and quantify heat transfer in the presence of free convection, and the results showed that the extent of transition zone 2 is small.

TL;DR: In this article, an experimental study of the flow pattern inside a model cylinder of a uniflow-scavenged two-stroke engine is presented, where the velocity field as well as the turbulent parameters were mapped under steady-flow conditions with the aid of a hot-wire anemometry technique.

TL;DR: In this article, gas holdup data (total and local) and the heat transfer coefficient between a 19 mm outer diameter heat transfer probe and an air-water dispersion are measured in continous and semibatch mode.

TL;DR: In this article, the photochromic flow visualization method (PFV) is used for experimental hydrodynamics, where tracers in the form of colored lines with a lifetime of 20-300 s are created by pulse radiation for 10 −9 s. The displacement of the tracers is followed by a high-speed movie camera.

TL;DR: An experimental study of developing and fully developed turbulent air flow in a square duct with two opposite rib-roughened walls in which the ribs are attached in a staggered fashion was conducted to determine the heat transfer characteristics as discussed by the authors.

TL;DR: In this paper, the characteristics of heat transfer of laminar natural convection between two isothermal vertical parallel flat plates in air at the ambient temperature and atmospheric pressure were investigated by using laser speckle photographic techniques.

TL;DR: In this paper, a cylindrical cavity filled with a fluid-superposed packed bed and heated from below is used for buoyancy-induced flow visualization and heat transfer experiments, where an immersion method is used to measure the refractive index of acrylic spheres, which is then matched with that of silicon fluid.

TL;DR: In this paper, a review of low quality transition and inverted annular flow film boiling of water in channels occurring after departure from nucleate boiling in temperature-controlled heat transfer systems is presented.

TL;DR: Kalinin et al. as mentioned in this paper developed an effective method to enhance heat transfer in tubular heat exchangers, and comprehensive studies were made of its effectiveness when applied to gas and liquid flow in tubes, circular channels, and inflow tube bundles over a wide range of performance parameters as well as to boiling and condensation of heat carriers.

TL;DR: In this article, an experimental study is reported of melting of a pure substance in a vertical rectangular enclosure that is partially occupied by horizontal or vertical layers of a relatively high thermal conductivity porous medium.

TL;DR: The application of detailed uncertainty analysis techniques in the debugging and qualification checks of a new turbulent heat transfer test facility is demonstrated and the data reduction equation for Stanton number is developed, and the associated uncertainty analysis is presented.

TL;DR: In this paper, a two-dimensional acoustic field was applied to lock the rate of vortex shedding from the leading edge separation bubble and set the mean reattachment length, which was found that large-scale vortex structures formed in the separating shear layer at the acoustic forcing frequency and shed into the turbulent boundary layer.

TL;DR: In this article, the flow pattern map in vertical heated pipes under steady-state and transient conditions, using Freon 12 in forced convective flow as working fluid and optical probes for the measurements, was determined.

TL;DR: Theoretical and experimental studies of laminar natural convective heat transfer in air from a pair of heated horizontal cylinders placed one above the other in the vertical plane were carried out in this paper.

TL;DR: In this article, the basic principles of liquid metal induction machines, pumps and generators are reviewed and a linear stability analysis is presented in which, for the first time, edge waves are taken into account.

TL;DR: In this paper, experimental design data (St vs Re, Nu vs x ∗, and f vs Re) are presented for four trapezoidal ducts with corrugated walls and one with smooth (noncorrugated) walls with constant wall temperature boundary conditions.