Bellmouth Research Articles

Improvement of Axial Dispersion by Intermittent Oscillatory Flow.

The efficiency of axial dispersion of respiratory gases is improved by manipulating the flow wave form of oscillatory flow, e. g., the intermittent oscillatory flow, contributing to the advancement of ventilation by high-frequency oscillation (HFO). The purpose of this study was to investigate experimentally the effect of intermittent oscillatory flow on axial dispersion. An electromagnetic vibrator was installed at one end of a straight tube, via the bell mouth, with the inner diameter of 15. 6 mm and the total length of 4 m. Velocity was measured by a hot-film anemometer, and the concentration of carbon dioxide was measured by an infrared absorption CO2 sensor. The effective diffusivity is dependent on the flow patterns, and the effective diffusivity increased significantly upon increasing the duration of stationary phase, with the maximum ratio of effective diffusivity to the molecular diffusivity double the that of sinusoidal oscillatory flow. Moreover, turbulence appears in the decelerating and stationary phase at high Reynolds numbers. In that case, the augmentation reached more than threefold. These results encourage effective use of intermittent oscillatory flow for ventilation by HFO.

Effect of socket (bell mouth) and end seal of butt joints on load bearing ability of ceramic pipes

This relationship varies as a function of the length of the tube and its average diameter Dav. An analysis of the deformation of the experimental pipes tested along the length showed that as I/Dav increases from 3.69 up to 8.87, the average magnitude of the deformation of pipes measuring 250 and 500 mm increases from 3.5 up to 5. This fact indicates that the deformation of the pipes along the length depends on their relative length. Figure i shows a plot of Csm/E p = f(I/Dav). We note that the plot developed for the loads corresponding to the beginning of working of the ceramic pipes in the second zone is linear ~mtep = 1,8 + 0,7UDav, where ~sm is the deformation of the smooth end; and ~p is the deformation of the socket (bell) region. At the same time, the Z/Day ratio is proportional to the parameter of rigidity R

Hot galvanizing of spiral tubes for irrigation farming

The Yakubovskii Pipe Plant in Voroshilovgrad has mastered the production of hot-galvanized spiral pipes for irrigation farming 180, 250, and 350 mm in diameter, 1.2-1.8 nun in wall thickness, and 5 m in length. The pipes are made from low-carbon cold-rolled steel strip by spiral forming. The ends of the strip are welded with high-frequency currents. The welding of a bell mouth and sphere onto the ends of the pipes ensures their rapid assembly in the field.

油圧システムの絞りにおけるキャビテーション

In this paper, caviation phenomena occanring at a restrictor in oil hydraulic system were investipted. As a result, the following conclusions were obtained.(1) In case of bell mouth choke which has a rounded entrance and in case of orifice plate, the cavitation occurs in the downstream apart from the outlet edge of the restrictor. On the other hand, in case of sharp edge choke, the cavitation occurs at the inside of the choke. (2) In case of sharp edge choke, the pressore at a place where the cavitation begins to be observed is much lower than the atmospheric pressure. But in case of bell month choke, the pressure is very high. (3) In case of bell mouth choke and of crifice plate, cavitation does not affect the discharge coefficient. But in case of sharp edge choke, the discharge coefficient is saffected by cavitation (4) In case of bell mouth choke, the critical outlet pressure at the beginning of cavitation for a certain value of inlet pressure becomes larger when the diameter of the choke is larger, the length of the choke is shorter, and the oil temperature is higher. (5) When a baffle plate is placed just behind the outlet end of bell mouth choke, noise doe to the cavitation is reduced.

An Experimental Study On Flow Field Around Inundate Bell Mouth Groin

A study was undertaken to investigate the flow field around bell mouth groin in a large mobile bed physical model facility (46m x 11 m). A total number of 24 test runs were conducted. Three different discharges and four different angles and two groin conditions (submerged and non-submerged) was considered. All tests were conducted for 8 hours duration in clear water condition. Velocity data have been collected forming grids in both vertical and horizontal direction around the vicinity of the bell mouth groin. Velocity was measured at 0.2, 0.4, 0.6 and 0.8 depths from the water surface by forming grids. Change in flow conditions around bell mouth groin for various test run have been analyzed non-dimensionally in longitudinal, lateral and vertical direction. The streamwise velocity along lateral direction was found that the lateral shifting of maximum velocity away from the head of the bell mouth groin. In most cases, streamwise vertical velocity in lower part of the channel is found higher than that of upper part. Streamwise vertical velocity profile has been found variable with different discharges and does not follow its natural logarithmic pattern. Velocity vector indicates that flow is steady at upstream along longitudinal direction. The flow diverted at head of structure and flows through sides of structure towards downstream. A circulation of flow has been observed around head of structure after diverting of flow towards down. Immediately after rear front of structure, relatively weak circulation of flow has been observed. In this paper the results of test runs conducted under submerged conditions for 1500 and 900 angles are reported. DOI: http://dx.doi.org/10.3126/kuset.v8i1.6050 KUSET 2012; 8(1): 104-118

Nature and Origin of Perispaptic Cells of the Motor End Plate

This chapter discusses the nature and origin of perisynaptic cells of the motor end plate. Studies of the cells composing the bell mouth of Henle surrounding the motor end plate indicate that it is composed of cells which are an extension of the perineural epithelium. The perineural epithelial cell membrane in turn is the continuation of the pia-arachnoid mater from the central nervous system. Thus the whole peripheral nervous system from its origin in the central nervous system up to and including the terminal end organs is completely enclosed in a cellular, protoplasmically intact, membrane composed of one or more layers of flattened squamous epithelial cells. These are perisynaptic cells, and are not Schwann cells (teloglia) but are a continuation of the perineural epithelium covering of that nerve which forms the motor end plate.

The Horizontal Wind Tunnel at East London College

The horizontal wind tunnel at East London College consists of a wooden tube, .2 feet square in section by lift. 6in. long, through which air may be drawn at velocities up to 50 m.p.h. by means of a 6½ h.p. motor. It was designed and constructed by Messrs. Cedric Lee and G. Tilghman Richards from sketches supplied by one of the authors and was modified later by the addition of a wind disperser as the result of information kindly supplied by Dr. Stanton, of the National Physical Laboratory. This disperser was added principally with the object of reducing the draught in the room and of preventing pulsations of the air current. The tunnel is provided with a bell mouth to ease the air into it, and at the other end it is connected to the disperser by a metal duct, 3ft. 6in. long, expanding from 2ft. square to 3ft. 6in. diameter. The propeller is mounted in the enlarged end, which is cylindrical for some 7 inches, so as to draw the air through the tunnel.