Round Orifice Research Articles

Flow Rate of Corn Through Orifices as Affected by Moisture Content

ABSTRACT THE flow rate of corn through round and square horizontal orifices was evaluated. Moisture content of the test corn lots, which ranged from 12.3 to 22.3% (w.b.), had a significant effect on both volume and mass flow rates. For the same size of orifice, the flow rate of corn increased as the moisture content decreased. An equation expressing volume flow rate of corn as a function of orifice size was obtained. The velocity of grain through an orifice increased almost linearly as the orifice size increased at given moisture contents.

Papillary morphology in adult human kidneys and in baby and adult pig kidneys.

The morphology of the renal papillae was studied by inspection in a series of: (1) Hampshire/Duroc piglet kidneys; (2) Danish Landrace adult pig kidneys, and (3) kidneys obtained at necropsy from adult patients. In both man and pig two main types of papillae were found: (1) a single or 'simple' papilla which drains one renal lobe, and (2) a fused or 'compound' papilla which drains two or more renal lobes. Compound papillae were found most frequently in the Hampshire/Duroc kidneys and least frequently in the human kidneys. In all three groups compound papillae were found most frequently in the upper pole. Intrarenal backflow during retrograde pyelography in the piglet kidney at intrapelvic pressures of 30-35 mm Hg (moderate) and of 70-75 mm Hg (high) was related to the morphology of the individual papilla. Both types of papilla could be divided into an open type containing at least two round or oval orifices of the papillary ducts and a closed type with small, often slit-like orifices. At moderate intrapelvic pressure intrarenal backflow occurred mainly in the open compound papillae whereas at high intrapelvic pressure it occurred in nearly all open compound papillae and in about 50% of the open simple papillae. It is concluded that papillary morphology plays an important role in the predominant upper polar occurrence of intrarenal backflow/intrarenal reflux during micturition cystography and in the higher frequency of intrarenal backflow in the mid-zone than in the lower pole in adult human beings.

ディーゼル機関用燃料噴射弁の流量特性

This paper is an investigation to determine flow coefficients of small round orifices of the sizes used with diesel engines. The values of the flow coefficients were obtained under injection pressures, under back pressures, and at oil temperatures of the area before the orifices.The results of this experiment showed that(1) The oil temperatures of the area before the orifices from 16°C to 51°C had no effect on the values of the flow coefficients.(2) The values of the flow coefficients were constant, independent of Reynolds numbers, under the back pressure 0 atg and under the injection pressures from 94 atg to 460 atg, and were not closely connected with Reynolds numbers under the back pressures above 0 atg.(3) The values of the flow coefficients, plotted against those of Euler numbers not those of Reynolds numbers, drawed a single curve.(4) The values of the flow coefficients became lower with the higher values of Euler numbers, and, unchanged with the above 200 values of Euler numbers.(5) The flow coefficients, Ct, were expressed byCt=k [0.705+0.829/ (1+Et) 1.03]where k=exp [-2.76 (log dt+0.405) 2-4.84 (logλ+0.521) 2- (lt/dt-3.36) 2×10-2]Et=Euler numberλ=dt/dsdt=diameter of orifice, mmlt=length of orifice, mmds=diameter of upstream section, mm.(6) The most suitable size of small round orifice wasdt = 0.394 mm, λ=0.301, and lt/dt=3.36.These experimental data will be useful in measuring the values of injection rate by pressure-lift method and in designing injection nozzles.

単ロール法急速凝固プロセスにおける融体衝突流動と金属薄帯形成

Metallic ribbon formation from a cylindrical melt jet in the single-roll rapid solidification process has been investigated to explore the dependence of ribbon geometry on the impinging melt flow on a rotating roll. Results of the experiment using round orifice nozzles and Pb-Sb eutectic alloy show that the spreading of melt on the roll increases with decreasing roll surface velocity and with increasing melt flow rate and melt temperature in nozzle. Effects of the key process parameters on the ribbon geometry are discussed through considering characteristics of the flow.Furthermore, the impinging flow is dimensionally and approximately analysed to obtain the equation (8) useful for estimating the melt spreading and the ribbon geometry. It has been cofirmed that the boundary layer flow in the melt puddle is laminar and that the melt temperature is about 11% lower in the puddle than in nozzle due to heat transfer to the roll. Effect of the melt surface tension on the ribbon formation can be neglected for Pb-Sb eutectic alloy, but not for Fe- or Cu-based alloys, whose ribbon width is well expressed by Eq. (18).

The Viscous-Gravity Jet in Stagnation Flow

Simple solutions are presented for the equation governing one-dimensional flow of very viscous jets that issue from a round orifice and fall against a flat plate. Due to the viscous axial stresses developed, the jet may be either in tension or compression, depending on the values of various dimensionless parameters involved. The comparison of the theoretical and experimental results is good.

Spray atomizer droplet spectrum measurement

AbstractThe gamma function distribution is used to discuss droplet size variation for flat fan and round orifice atomizers. A technique of using multiple‐probe devices to measure droplet size, distribution and flux when the form of the distribution is known is described. Experimental results with a four‐unit conductance probe device are given for a Spraying Systems Tee‐jet operating with a slightly conducting liquid at 4.2 dm3/s and at an air velocity of 75.6 m/s. Probe results give a mass mean diameter of 68 μm while the standard photographie method gives 78 μm. A material balance using probe results gives a liquid flow of 6.0 dm3/s. The accuracy of this method is easily improved by adding more units, but the restrictions of conducting liquid and the mechanical problems of probe construction and calibration indicate that optical probes should be investigated.

Aerodynamic study of turbulent burning free jets with swirl

Velocity and temperature measurements have been made in a series of turbulent swirling free flames. Premixed butane-air jets issued from a round orifice with exit velocities of 60 m/sec and the degree of swirl was varied by varying the ratio of the flow rates of air supplied tangentially and axially to the burner. The flames were stabilized some 4 diameters from the burner exit in the shape of an annular ring and were unconfined for a distance of 24 diameters. The measurements made in this region for 3 different degrees of swirl show that the decay of axial and swirl velocities is slower in a flame than in cold swirling jets. The turbulent burning velocity was found to be 80 times greater than the laminar burning velocity and the velocity gradient in the outer region of the jet where the flame was stabilized was 250 cm−1. In the theoretical analysis the turbulent equations of motion, energy and state have been integrated to obtain expressions for the decay along the axis of the maximum values of axial velocity, swirl velocity and temperature. Variations in flame shape are described in terms of velocity decay constants and Gaussian error curve constants for radial spread of temperature and velocity.

Entry effects in the open thermosyphon

In this paper flow-visualization techniques are used to study the flow instability which occurs at the orifice in the free convection open thermosyphon. The influence of the shape of the orifice on the measured heat transfer of the system is also studied under both laminar and turbulent conditions. The dominant mode of penetration of the hot stream by the cold fluid entering at the base of the reservoir is found to instigate a mixing region at the orifice. In turbulent flow this spreads into and eventually fills the tube as the Rayleigh number is increased. In such circumstances a sharp-edged orifice appears to give better overall heat transfer than a rounded orifice.

Teflon Dropping Mercury Electrode for Polarography in Hydrofluoric Acid and Other Glass-Corroding Media.

A Teflon D.M.E. satisfactory for polarography in glasscorroding media was developed for the first time. It is dimensionaliy stabie and has a round smooth-walled orifice that can be made to within plus or minus 10 microns of a specified diameter, a lapped face, and a bore of shape that can be varied. Teflon D.M.E.s of orifice diameter in the range from 15 to 110 microns were made. Satisfactory geometric and performance characteristics were proved by means of photomicrography and high-speed motion-picture photography and by determining: the nature of drop formation; values of m, t, and w; electrocapillary curves; current-voltage recordings; polarographic reduction waves; and a diffusion current vs concentration curve. Data were taken for glasscorroding solutions of hydrofluoric acid and sodium hydroxide. Reference data were taken for a glass D.M.E. in several media that do not corrode glass. The Teflon D.M.E. behaves essentially the same as a glass D.M.E. The few differences in behavior favor use of the Teflon D.M.E. It appears that certain data taken with glass and Teflon D.M.E.s can be intercompared.

Transfer of heat and matter in the turbulent mixing zone of an axially symmetrical jet

This paper describes results of measurements concerning the radial and axial distribution of time-mean values of velocity, temperature, and gas concentration in a turbulent jet issuing from a round orifice into quiescent ambient air. The results show that the rates of spreading of heat and matter are mutually equal but greater than that of velocity. A constant ratio between the coefficient of transfer of heat or matter and the coefficient of shearing stress does not seem to exist. The results have been subjected to a theoretical analysis.