The Hazen-Williams equation is an empirically derived formula that describes the velocity of water in a gravity flow. A = 0.0201 m 2. Pipe cross-sectional area could be obtained by the following formula. Physical values in Darcy formula are very obvious and can be easily obtained when pipe properties are known like D - pipe internal diameter, L - pipe length and when flow rate is known, velocity can be easily calculated using continuity equation. Moreover, in this topic, you will learn about the flow rate, flow rate formula, formula’s derivation, and solved example. Hazen-Williams equation. Pipe cross-sectional area ＝ ID² / 4 Xπ (ID stands for pipe inner diameter, π stands for Pi which is 3.14) Flow rate = Pipe cross-sectional area X Flow speed. The volumetric flow rate of a stream of liquid or gas is equal to the flow velocity multiplied by its the cross-sectional area. Therefore, the formula for flow rate (Q), also known as "discharge rate" expressed in terms of the flow area (A) and its velocity (v) is the so-called discharge equation: The resulting Q is the volumetric flow rate. Also, its current depends on the diameter of the pipe. In the case of a round pipe the cross-sectional area is the inner diameter divided by 2 times π while if it is rectangular the area is the inner width times the inner height. It also doesn't take into account the temperature of the water, and is only accurate for the 40-75 °F (4-25 °C) range. The area of the pipe is 0.0201 m 2. Flow Rate Formula Questions: 1) Water is flowing through a circular pipe that has a radius of 0.0800 m.The velocity of the water is 3.30 m/s.What is the flow rate of the water in liters per second (L/s)?Answer: The flow rate depends on the area of the circular pipe: A = πr 2. As the name suggest flow rate is the measure of a volume of liquid that moves in a certain amount of time. With the below formula, we can understand the relationship between flow rate, flow velocity, and pipe diameter. Remember that the Hazen-Williams equation is valid only for water - applying it for any other fluid will give you inaccurate results. A = π(0.0800 m) 2 A = π(0.00640 m 2). The equation can b…