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Here, HL.LargeScaleMixing and HL.SmallScaleMixing refer to the minor losses through the large and small scale mixing orifices, respectively. HL.PipeFittings and HL.PipeFriction are caused by minor losses through the pipe fittings and major losses sue to shear along the pipe walls.

Flow through both the large and small scale orifices is modeled as an expansion; as the water flows through the orifices, the flow is contracted and then expands on the other side of the orifice. Thus, head loss can be calculated using the equation for head loss in a flow expansion:

Image AddedNeed a ~paragraph here explaining how the head losses for each component are calculated

The calculation of the headloss through the system is important because the headloss through the rapid mix tube system partially determines the change in height of the water in the entrance tank when the plant flow changes. The nonlinear chemical doser is designed to change the flow rate of alum with the flow rate of the plant, and it is thus very important to calculate the headlosses through the rapid mix tube system and the sections of the plant following it in order to correctly design the chemical doser to maintain a constant concentration of alum in the raw water source despite changing flow rates.

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