T
thartley
This may be trivial, but when solving pipe problems that use the energy equation and using an equation like the Hazen-Williams equation to solve for the friction losses, I have found it very useful to modify it from its standard form when storing it in the HP 33S. Instead of entering separate variables for the Area and the hydraulic radius, I enter it so that it uses the pipe diameter instead for those variables. Here's what I mean:
Instead of A^1.85 , I use (pi X D^2/4)^1.85 since A=(pi X D^2/4) ..... (pi/4xD^2) will also work
and instead of R^1.17 , I use (D/4)^1.17 since R=(D/4)
(When the equation is entered into the 33S it doesn't look exactly as typed here - the computer keyboard doesn't have the "divide" button so I substituted a forward slash as well as the word "pi" to represent a right-shift+COS to get the pi symbol in the calculator)
With the equation stored into the calculator this way, I can use the Solver feature of the 33S to solve for the pipe diameter directly. At least with the practice problems I've been doing, many times this has been one of the items that I've been asked to solve for. If the problem doesn't ask me to solve for the diameter, then the diameter is one of the values given in the problem statement. This also saves me time having to calculate the area and hydraulic radius in order to enter them into the equation. I have one less variable to provide an input value for.
The one drawback that I've noticed when solving for the diameter is that it takes several seconds for the calculator to come up with a solution. It seems to take about 3 times as long compared to solving for H or Q.
Instead of A^1.85 , I use (pi X D^2/4)^1.85 since A=(pi X D^2/4) ..... (pi/4xD^2) will also work
and instead of R^1.17 , I use (D/4)^1.17 since R=(D/4)
(When the equation is entered into the 33S it doesn't look exactly as typed here - the computer keyboard doesn't have the "divide" button so I substituted a forward slash as well as the word "pi" to represent a right-shift+COS to get the pi symbol in the calculator)
With the equation stored into the calculator this way, I can use the Solver feature of the 33S to solve for the pipe diameter directly. At least with the practice problems I've been doing, many times this has been one of the items that I've been asked to solve for. If the problem doesn't ask me to solve for the diameter, then the diameter is one of the values given in the problem statement. This also saves me time having to calculate the area and hydraulic radius in order to enter them into the equation. I have one less variable to provide an input value for.
The one drawback that I've noticed when solving for the diameter is that it takes several seconds for the calculator to come up with a solution. It seems to take about 3 times as long compared to solving for H or Q.
