Question 27: Net positive suction head of centrifugal pumps on the first day of 2011 at 2 p.m
Thread Content
The design flow rate of the centrifugal pump is 30 m3/h, and its rotational speed is 2900 r/min； When calculating the required net positive suction head value for this pump, which of the following values should be used? A、4.1 B、3.1 C、2.1 D、1.1 I have no idea where to start; it’s frustrating.
hgt20570.5 Formula 3.0.1-1
Don’t be afraid of this type of question – just apply the formula directly!
NPSH=(nsqrt(Q)/1200)^4/3, where Q is in m3/min; the result is 2.1
The problem is not knowing which books to bring. At the moment, I only have the textbooks from Tianjin University and the association, as well as some standards. There are too many HGT20570 entries – do I need to check them all?
Expert! I’m not from a chemical engineering background, so I don’t know the sources for many of these things. One can only rely on the textbooks, but many things aren’t covered in them.
Examining the design standard HG/T20570 – a tricky question! Most people get it wrong! This deserves attention!
Basically, these are enough; the key is to be familiar with them. If you just bring them in, there are over a thousand pages, and it will be impossible to find what you need when looking through them. Additionally, doing more exercises is the best approach
The formula can also be found on page 694 of the association’s book; it seems I didn’t read it carefully enough