Stop looking at pressure drop like this

[@SoulofaPond]

The fundamentals of all reverse osmosis operations put down to the T. You have quantity, you mentioned quality but also don't forget efficiency. Energy vectors, tds, anything that you are aiming for matters on the trinity. Thank you again

[@ProcesswithPat]

Brilliant addition! Maybe we should have you on some time?

[@SoulofaPond]

@@ProcesswithPat happily at your disposal grand mind

[@FirstnameLastname-fn6ik]

I hope this channel continues for a long time, every video is a knowledge gem for me!

[@ProcesswithPat]

Thanks for that! That’s the idea, I don’t wanna make videos that feel too much like lectures/something you can find elsewhere. There has to be some insight air application. Really appreciate it.

[@NikolayBychkovRus]

​@@ProcesswithPatI support the comment waiting for new videos:)

[@ronnysharma6767]

This is such a good point. Another important thing to point out is that as downstream pressure decreases, you start to generate more flow. I've seen situations where pressure control valves downstream of fixed speed pumps have been left in manual, and the down stream pressures started to decrease over time due to process related reasons. This ultimately caused flow to increase, and almost caused a safety system in the plant I was working at to activate. So this concept is super important to understand!

[@alecslungaard4749]

Fantastic video. Thank you for adding visuals to accompany your insightful description of pressure drop. Keep up the great work!

[@Jh-uy6qj]

Which equation are you using to derive the square law for DP and Flow? Bernoulli requires a change in area to get that result but that wasn’t explicitly stated, is it Darcy-Weisbach?

[@ProcesswithPat]

I didn't strictly "derive" it. It is a knock-on effect from bernoully, where dP is proportional to velocity squares, but as I say, some equipment is shaped such that the exponent isn't necessarily a 2... It could be 1, 1.5, anything. It's just a rough application when I don't have data. But if you have actual data for flow vs dP, you should fit it.

[@camibabyy]

Is the square relation you showed for both liquid and gas? If it's gas don't you need to consider temperature? Or are you assuming isothermal? -- 3rd yr ChemE student

[@ProcesswithPat]

Generally yes, it’s for both liquids and gases, and absolutely temperature will play a role because pressure drop is related to density. Just keep in mind that it isn’t always a square relationship in all instances - that’s why we develop complicated equations and charts for pressure drops of things like heat exchangers. Nevertheless, scaling the pressure drop using a square relationship is better than using a fixed high alarm for all flow rates.

[@carultch]

Pressure drop is extremely non-linear, and there isn't a closed-form equation that describes it. For laminar flow of Newtonian fluids, it is a linear relationship between flow rate and pressure drop, that is a 1-to-1 analogy to Ohm's law in electrical circuits. For extreme turbulent flow, in the limit of high Reynolds' numbers, it asymptotically approaches a parabolic relationship, where pressure drop is approximately proportional to the square of flow rate. For transitional flow and moderate turbulent flow, there is no closed-form equation derived directly from theory, and the process to calculate this relationship is very round-about and indirect. There are empirical equations and charts based on generalizing flow in terms of Reynolds' number, and forming a curve-fit to the experimental results. This is what is used for predicting pressure drop from flow, or vice-versa. Most flows of water and air are turbulent. Laminar flow usually happens for more viscous fluids like oils.

[@rasmussverdrup7479]

Are you using bitcoin as an example of the intrinsic value of an object? Bold choice & Great video!

[@ProcesswithPat]

Don’t pretend you wouldn’t buy it if I offered it to you at that price! But yes, I thought It’s be hilarious to see how well (or poorly) this video ages.

[@rasmussverdrup7479]

​@@ProcesswithPat To be honest I often go to friction or pressure drops to explain concepts like inflation, value and other economics stuff. But I mostly talk to my kids, so I could basically say anything.