When you need to measure flow, a flume is perhaps your best choice for a primary device, and this is particularly true when you need to measure piped flow. When connecting a flume to a pipe for measurement purposes, there are several factors that you will need to take into account, including the slope of the pipe.
The slope of the pipe will directly impact the speed of the flow, and if you don’t consider this factor, you may not be able to take the accurate measurements that you need. Learn more about how pipe slope can affect your flume operations, and find out how to make adjustments so that you can take accurate readings.
Basics of Flume Operations
Before learning about how pipe slope can affect your flume, it’s a good idea to cover a few basics of flume operation. The basic function of a flume is to take subcritical flow and accelerate it into a critical state. Accelerating the flow allows your operators to measure the flow rate by taking measurements at a single point. Not only is this convenient, it also increases the overall accuracy of your operation.
For your flume to operate correctly, the flow entering must be in a subcritical state, which can be difficult based on the slope of your pipe.
What’s in a Froude Number?
When you’re trying to determine whether the flow entering your flume is subcritical, critical, or supercritical, you would examine the Froude number. If the Froude number of your flow is below one, then the flow is considered subcritical, which is ideal when entering a flume. A Froude number of 1 means your flow is critical, and anything more than 1 is supercritical.
Clearly, to make sure that your readings are as accurate as possible, the flow exiting your pipe and entering your flume should have a Froude number of 1. However, you should shoot for a Froude number of 0.5.
How Pipe Slope Affects the Froude Number
The reason it’s so important to consider the slope of your pipe is that it can directly affect the Froude number of your flow. As the slope of your pipe increase, it will also increase the Froude number, which can make it difficult to maintain a subcritical state. In addition, the size of your pipe can increase the impact the slope has on your Froude number.
Fortunately, for every size of pipe you could use, there are a range of pipe slopes that will result in subcritical flow. If your slope exceeds this range, however, you will need to make adjustments before you can install your flume.
Help Choosing Your Flume
While a flume is the best choice for measuring piped flows, there are several factors that can impact the accuracy of your reading, including the slope of your pipe. If you want to make sure your operation is as successful as possible, you need the right tools, which is why you should work with the team at Tracom, FRP.
Tracom manufactures and sells fiberglass water management products that will match your exact needs. We offer flumes and a wide range of other useful tools. Contact us today to request a product quote.