Abstract: A headbox for paper-making machines comprises at least one bundle of throughflow pipes in the flow channel between the distributing pipe which feeds the pulp and the discharge nozzle. The throughflow cross-section of the bundle of pipes or throughflow pipes (16, 27, 38) can be varied across the width of the headbox for the purpose of controlling and/or adjusting the headbox.

Abstract: The paper describes a theoretical treatment for nucleating throughflow of steam in a turbine stage. The conservation equations governing the overall behaviour of the fluid are combined with those describing droplet behaviour and treated by a time-marching method. The computer program developed has been applied to some test cases and comparisons are presented between solutions allowing for non-equilibrium effects and those in which steam has been assumed to remain in thermodynamic equilibrium.

Abstract: A device for measuring the mass flow of materials according to the Coriolis principle comprises a throughflow device through which the fluid flows and whose throughflow is to be measured, an exciter device which imparts an oscillating movement perpendicular to the direction of flow to the throughflow device, and sensors, arranged at at least three measuring points along the flow device and which emits signals characteristic of the phase relationship of the oscillating movements of the throughflow device at each measurement. An evaluation unit receives the sensor signals from which it derives a phase shift generated by the Coriolis forces which is an index of the throughflow. In order to detect errors in the mass flow measurements, the evaluation unit derives the phase differences from the sensor signals from two measurement points, compares the phase differences so obtained, and indicates an error when differences are detected.

Abstract: The desired measurement values(s) is/are derived from a measuring signal obtained from a pressure difference, the effect of force on a choke and/or baffle element, a thermal, acoustic, optical or electrical signal. The measuring signal enables the vol. as well as the mass throughflow and density to be ascertained. In addition to throughflow the viscosity cane be determined. The flow through a pipe cane be confined by a throttle element and/or affected by a baffle element. For differential pressure measurement, a first pressure pick-up point is set in-front of the baffle and/or throttle element and a second one behind. A thermal or electrical signal is derived from a thermistor p.t. c. or n.t.c. resistor or a heated wire near the throttle or baffle element. ADVANTAGE - No movable or vibrating parts required. Measuring pick-up cana be made very compact, simple and robust.

Abstract: The subject of the present theoretical and experimental work is laminar flow processes in the gap between a rotating disc and a stationary wall. A report is given of the creation of suitable computational methods for determining the pressure gradient and velocity field in the impeller-side space of specifically slow-working rotary pumps in the process of conveying very viscous media with Newton properties, given temperature-dependent viscosity. The exposition is based on the abstract model conception of parallel radial gaps, the resultant frictional torques and the axial forces being determined for the case of a superimposed throughflow. On the one hand, the basis of the computations is an implicit difference method, and on the other an asymptotic computational method which leads to success via disturbance estimates in conjunction with similarity transformations, and approaches the difference method in accuracy while being relatively simple to handle and requiring little expenditure of time. On the basis of the computational results, experiments are conducted using a suitable experimental set-up, which answer the question concerning the efficiency and area of validity of the computational model.

Abstract: What is described is a throughflow-quantity limiter for a pipeline carrying water, oil or the like, with the use of a shut-off member and of a flow-detection member with a contact-maker for the transmission of pulses to a time relay which acts on the shut-off member, in which through-flow quantity limiter a bypass line, in which a flow-detection member is arranged, is provided parallel to a portion of the pipeline which follows in a throughflow direction a portion of the pipeline having a shut-off member. As a result, the flow-detection member is capable of already reacting to minimum throughflow quantities with uniformly high accuracy in the case of pipeline cross-sections of varying size, both in normal operation and in the event of a fault.

Abstract: : The finite element code Q3DFLO 81 was evaluated to determine its suitability for use in a program to investigate axial compressor tip clearance effects. The code was first applied to Dring's fully comprehensive benchmark data set in order to validate the numerical modelling free of experimental uncertainties. It was then applied to the Naval Postgraduate School axial research compressor with which tip clearance effects were to be investigated experimentally. The evaluation identified both limitations in the code and limitations in the data which could be obtained in the experiment. It was recommended that provision be made to accommodate peripherally non-uniform flow effects (blockage) in the throughflow code calculation, and that provision be made to obtain adequate peripheral flow surveys in the experiment. Throughflow analysis, Blockage, Rotor tip clearance studies, Axial flow compressor, Hydraulic equipment. (jes)

Abstract: of EP01951781. Throughflow and closure valve having at least three discs, as sealing and control elements, located one below the other and of similar construction and having throughflow passages, the two outer discs of which are fixed whilst the middle disc is movable, the discs having sealing surfaces, characterised in that in the closed state of the valve the sealing surface or surfaces (24, 28) of the middle disc (12) co-operates or co-operate with the sealing surface or surfaces (25, 32) of the one outer disc (11), whilst at the same time the throughflow passage or passages (16) of the middle disc (12) remains or remain in communicating connection with the throughflow passage or passages (16) of the other outer disc (13).

Abstract: The filter-holder is characterised by having two outlet devices (7, 17), one (7) of which has a smaller throughflow cross-section and an inlet opening (15) in the immediate vicinity of the holder bottom (4), and the other outlet device (17) of which has a larger throughflow cross-section and an inlet opening with spacing above the inlet opening (15) of the first outlet device, the throughflow cross- section of the first outlet device being so small that the column of liquid between the filter paper and the container wall drops so slowly that the column of liquid in the filter paper remains in contact with the ground coffee for a sufficiently long time in the case of a certain minimum amount of coffee.

Abstract: Subsurface water flow routes have been inferred from gypsum sphere weight loss with minimal disturbance to soil structure or flow nets (Crabtree and Trudgill, 1984). This technique is limited by the relatively slow, fixed dissolution of gypsum. A solution is to use tablets consisting of Durham's ‘Rock Hard Water Putty’ and sodium sulphate. Laboratory tests indicate that tablet dissolution is controlled by the ratio of Rock Hard to sodium sulphate and is proportional to net throughflow yet independent of throughflow pH (between 3·0 and 9·0) and throughflow rate (at rates < 0·04 1 hr−1). The tablets are also mechanically stable, economical, and environmentally safe. Field study results using the Rock Hard-sodium sulphate tablets are consistent with both the laboratory findings and the results of previous investigators.

Abstract: A 3-D Navier-Stokes code was developed for analysis of turbomachinery blade rows and other internal flows. The Navier-Stokes equations are written in a Cartesian coordinate system rotating about the x-axis, and then mapped to a general body-fitted coordinate system. Streamwise viscous terms are neglected using the thin layer assumption, and turbulence effects are modelled using the Baldwin-Lomax turbulence model. The equations are discretized using finite differences on stacked C-type grids and are solved using a multistage Runge-Kutta algorithm with a spatially varying time step and implicit residual smoothing. Calculations were made of the flow around a supersonic throughflow fan blade. The fan was designed as a key component in a supersonic cruise engine. The 3-D calculations were done on a 129x29x33 grid and took 50 minutes of cpu time. Comparisons with the quasi-3-D results show minor differences in loading due to 3-D effects. Particle traces show nearly 2-D flows near the pressure surface, but large secondary flows within the suction surface boundary layer. The horseshoe vortex ahead of the leading edge is clearly seen.

Abstract: The saturation-paste extract (SPE) chemistry of samples collected in the wet-meadow and shallow-marsh zones of seven North Dakota wetlands was related to SPE electrical conductivity to investigate the development of hydric-soil salinity. Study wetlands represent a local, depression-focused groundwater-flow system. Recharge wetlands recharge the groundwater whereas discharge wetlands receive the majority of their water as groundwater discharge. Throughflow wetlands receive water from as well as yield water to the system. Development of soil salinity generally followed the Hardie and Eugster model of closed-basin brine evolution, which considers the composition of solutions undergoing evaporation to be the result of chemical changes imposed by the successive formation of evaporite minerals. Hydric soils of recharge wetlands were nonsaline and free of calcite (CaCO3) and gypsum (CaSO42H2O). The chemistry of these soils results from evapotranspiration, recharge hydrology, ionic mobility, and exchange relationships. Increases in SPE Mg, Na, and dominance in more saline throughflow and discharge wetlands are caused by calcite and gypsum precipitation, with the former controlling alkalinity and the latter Ca concentrations. At high salinities produced by concentration through freezing, mirabilite (Na2SO410H2O) crystallizes and controls Na levels, resulting in hypersaline solutions enriched in Mg and Additional variation in the patterns of salinity development can be explained by dominance of recharge over discharge, mixing with fresh or chemically discrete water, and valence dilution effects. View complete article To view this complete article, insert Disc 5 then click button8

Abstract: Rayleigh-B?nard convection in the presence of a horizontal throughflow perpendicular to the convective roll chain is investigated with a 1d amplitude equation and with a 2d numerical simulation of the basic hydrodynamic equations. Results agree very well with each other. The flow leads to propagating convective patterns in the form of travelling wave states which for increasing flow are localized further and further downstream. Unique wave number selection is observed. Related experiments are discussed.