Discharge Coefficient for Free Jets From Orifices at Low Reynolds Number

1993 ◽  
Vol 115 (4) ◽  
pp. 778-781 ◽  
Author(s):  
Tomasz Kiljan´ski
Keyword(s):  
Reynolds Number ◽  
Discharge Coefficient ◽  
Low Reynolds Number ◽  
Free Jets ◽  
Low Reynolds

Experimental analysis of low-Reynolds number free jets

2009 ◽  
Vol 47 (2) ◽  
pp. 279-294 ◽  
Author(s):  
Valentino Todde ◽  
Pier Giorgio Spazzini ◽  
Mats Sandberg
Keyword(s):  
Reynolds Number ◽  
Experimental Analysis ◽  
Low Reynolds Number ◽  
Free Jets ◽  
Low Reynolds

Profiles for Low Reynolds Number Flows

1968 ◽  
Vol 183 (1) ◽  
pp. 591-602 ◽  
Author(s):  
G. S. Vasy ◽  
L. J. Kastner ◽  
J. C. McVeigh
Keyword(s):  
Reynolds Number ◽  
Discharge Coefficient ◽  
Low Reynolds Number ◽  
Small Diameter ◽  
Reynolds Numbers ◽  
Number Range ◽  
Low Reynolds Number Flows ◽  
Low Reynolds ◽  
Reynolds Number Flows ◽  
Considerable Range

The characteristics of the orifice meter are well known and have been thoroughly explored by a number of investigators over a considerable range of Reynolds numbers, yet the low Reynolds number range—i.e. below ( Re D = 4000, where ( Re) D is the upstream pipe Reynolds number, has received comparatively little attention, although recent work by two of the authors has supplemented the available data substantially. This work concentrates on very accurate measurements with small diameter orifices, but where less exacting standards of metering accuracy, e.g. ±2-2 1/2 per cent, can be allowed, a closer analysis reveals that there is a choice of orifice profiles which can be used successfully. Consideration is also given to the recommendations of the various standardizing bodies for the allowable tolerances in the diameter of the pipeline in which the orifice meter is situated. These tolerances are often unnecessarily severe and a ‘tolerance number’ depending upon discharge coefficient and the area ratio of orifice to pipe is suggested.

Modelling the Conical-Entrance Orifice Plate Flow Sensor

1995 ◽  
Vol 17 (3) ◽  
pp. 155-160
Author(s):  
Y. S. Ho ◽  
F. Abdullah
Keyword(s):  
Reynolds Number ◽  
Discharge Coefficient ◽  
Low Reynolds Number ◽  
Reynolds Numbers ◽  
Flow Sensor ◽  
Orifice Plate ◽  
Measuring Device ◽  
Reynolds Number Flow ◽  
Number Flow ◽  
Low Reynolds

This paper presents a numerical model for the conical entrance orifice plate flow sensor, which is essentially used as a low Reynolds number flow measuring device. The model was developed using a low Reynolds number k-ɛ model of turbulence – the Lam and Bremhorst model. Numerical results were obtained for diameter ratios of 0.1, 0.2 and 0.3, and for pipe Reynolds numbers of between 80 and 60000. The computed discharge coefficients are compared with available experimental data and with the value stated in BS 1042. Results show that the model developed can predict the discharge coefficient to within ±3% for the range of diameter ratios and Reynolds numbers investigated.

A Reassessment of Metering Orifices for Low Reynolds Numbers

1965 ◽  
Vol 180 (1) ◽  
pp. 331-356 ◽  
Author(s):  
L. J. Kastner ◽  
J. C. McVeigh
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
Low Reynolds Number ◽  
Reynolds Numbers ◽  
Number Range ◽  
Low Reynolds Numbers ◽  
Discharge Coefficients ◽  
Low Reynolds

In view of the importance of accurate measurement of flow rate at low Reynolds numbers, there have been numerous attempts to develop metering devices having constant discharge coefficients in the range of pipe Reynolds numbers between about 3000 and 200 and even below this latter value, and some of these attempts have achieved a reasonable degrees of success. Nevertheless, some confusion exists regarding the dimensions and range of utility of certain designs which have been recommended and further information is necessary in order that the situation may be clarified. The aims of the present investigation, which is believed to be wider in scope than any published in this field in recent years, were to review and correlate existing knowledge and to make an experimental study of the properties of various types of orifice in the low range of Reynolds numbers. Arising from this it was hoped that a design might be evolved which not only had a satisfactorily constant discharge coefficient throughout the range but was also simple to manufacture and reproduce, even for small orifice diameters of the order of 0.5 in or less, and it is believed that some success in attaining this aim was achieved. The first section of the paper contains a review of previous investigations classified into three main groups. In the second part of the paper, experiments with various types of orifice plate are described and it is shown that a properly proportioned single-bevelled orifice has as good a performance in the low Reynolds number range as that of any of the more complicated shapes.

A Theoretical Model for the Transverse Impingement of Free Jets at Low Reynolds Numbers

1980 ◽  
Vol 102 (4) ◽  
pp. 510-518 ◽  
Author(s):  
R. Winton ◽  
H. R. Martin
Keyword(s):  
Reynolds Number ◽  
Theoretical Model ◽  
Fluid Mechanics ◽  
Low Reynolds Number ◽  
Reynolds Numbers ◽  
Exit Plane ◽  
Suction Force ◽  
Free Jets ◽  
Low Reynolds Numbers ◽  
Low Reynolds

There are many applications in industrial fluid mechanics and fluidic technology where jets of fluid interact. This paper examines the interaction of two liquid laminar free jets under low Reynolds number conditions and particularly highlights the phenomenon of the inwards deflecting jet. A potential flow solution is developed for the modelling of the control jet flow in the vicinity of the control nozzle exit plane, which demonstrates the presence of a net suction force modifying the momentum interaction of the two orthogonal jets under these low Reynolds number conditions.

Numerical and experimental investigation of tip leakage flow and heat transfer using idealised rotor-tip models at transonic conditions

2009 ◽  
Vol 113 (1141) ◽  
pp. 165-175 ◽  
Author(s):  
S. K. Krishnababu ◽  
H. P. Hodson ◽  
W. N. Dawes ◽  
P. J. Newton ◽  
G. D. Lock
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Discharge Coefficient ◽  
Fluid Dynamic ◽  
Low Reynolds Number ◽  
Analytical Models ◽  
Tip Leakage Flow ◽  
Mach Numbers ◽  
Low Reynolds

Abstract The effect of tip geometry on discharge coefficient and heat transfer is investigated both experimentally and numerically using idealised models of an unshrouded rotor blade. A flat tip was compared with two squealer-type geometries (a cavity and suction-side squealer) under the transonic conditions expected in the gas turbine engine. Heat transfer measurements were performed using a transient liquid crystal technique while a duplicate test section was used for measuring the pressure field. Computations were carried out using an unstructured, fully compressible, three-dimensional RANS (Reynolds averaged Navier Stokes) solver. Initial computations performed using a low Reynolds number k-ε model demonstrated the inability of the model to predict the Nusselt number with reasonable accuracy. Further computations performed using a low Reynolds number k-ω model improved the predictions dramatically. The computed discharge coefficient and the average Nusselt number over the blade tip agreed well with the experiments. Three upstream-total to exit-static pressure ratios were used to create a range of engine-representative Mach numbers. Both experimental and numerical studies at the lower pressure ratio of 1·3 (exit Mach number ~ 0·65) established the cavity geometry as the best performer from an aerodynamic perspective by reducing the discharge through the tip. However, from the heat transfer perspective, both the peak Nusselt number and the average heat transfer to the tip were higher than the flat tip. At the higher pressure ratios of 1·85 and 2·27 (corresponding to exit Mach numbers ~ 0·98 and 1·12) the discharge coefficient and heat transfer to the tip increases. This paper explores the fluid dynamics associated with these flows and shows that the highest heat transfer is caused by reattachment and flow impingement. The fluid dynamic computations provide insight into the experimental measurements and were successfully compared with simple analytical models.

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