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* Add a section on the algorithm used to design the LFOM. Show the equations and add sketches that illustrate the design algorithm.
* Note that we may want to modify the algorithm slightly to make it more accurate.
* Also review the design algorithm to make sure that it is coded as simply and elegantly as possible. We will probably not include the code in this paper, but the code should be available from the wiki.
* Show some comparisons of designs (hole patterns).
* Investigate and discuss other design constraints including
** maximum flow of water through an LFOM as a function of pipe diameter
** the effect on accuracy of the ratio between vertical spacing of orifices and range of measurement
** the effect of the orifice diameter on accuracy (perhaps show the expected departure from linearity as a function of the total number of orifices in the LFOM)
* Add several LFOM designs for different flow rates.
* Include the possibility of using multiple LFOM to get a desired flow rate.
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2. Materials and Methods
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Experimental set-up
The Sutro weir shape is dictated by a series of equations. This doesn�t sound right. Do you have the reference to the Sutro weir design to see how it was created? Did Sutro get an analytical solution to the shape of the curve or did Sutro use a finite difference scheme? Approximating the weir for design of the LFOM was achieved through a computer program in MathCAD that simultaneously solve the equations and designs a template for orifice location and quantity on the LFOM riser pipe. The program requires input of maximum flow rate through the water treatment plant and then through iteration selects the largest drill bit size Describe this algorithm in more detail. that is able to theoretically mimic the Sutro weir with 10% this is the error you are reporting. So is this the error that you should have expected? Would it be possible to improve this accuracy simply by changing this constraint in the design algorithm? accuracy. The large orifice size is beneficial because obstructions are common in untreated water and large orifices are less likely to clog. Clogged orifices result in increased water height and an over estimate the flow rate. Using larger orfices also make construction easier since fewer holes need to be marked and drilled. A LFOM and entrance tank were designed for implementation in the AguaClara pilot plant with a maximum flow rate of 125 L/min. The LFOM is fabricated from a 3" nominal diameter schedule 40 PVC pipe with an orifice diameter of 9.525 mm (3/8"). The total vertical range of the LFOM was set to be 20 cm. This matches the vertical spacing using in AguaClara water treatment plants for regulation of chemical dosing. Every centimeter was evaluated for necessary orifices. How would accuracy be affected if the spacing were set to 2 cm or some other interval? The water from the plant flows into the entrance tank, a five gallon bucket, and through the riser pipe into the flocculation tank. In-line with the water inflow pipe a flow meter, Siemens model SITRANS F M MAG 3100, is installed. The device provides flow measurements with an accuracy of +/-0.25% of flow rate.
Measurement of Water height in Entrance Tank as Flow Rate Fluctuates
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