Hello, Thanks for the video. I have 2 questions and 1 comment :) 1. In line 7) of your calculation (approx. 09:35 - :09:50): Why do you use a factor of 2 i.e. 2 x 0.0046 x ... x 35 /diameter. You are calculating the loss in the pipe which there is 1 off. (There are 2 bends, hence a factor of 2, OK) 2. In line 7) of your calculation (approx. 10:06): Why do you use 0.00291 m for the pipe diameter when you at the start says it is: 0.0291 m (a decade in difference). 3. Also, the friction factor of 0.0046 ...? Does such a smooth pipe exist? (The value is outside my Moody diagram).
In line 7, the factor "2" is part of the equation, please see the derivation. Ef =2 x f x u^2 x L/D The denominator term for Diameter should be 0.02291. In fact, in the calculation, the correct diameter is used. The resulting value of 187.2 is correct. Thank you for noting this, I will make the correction in the video. The friction factor of 0.0046 is correct. Please recheck the Moody diagram.
Hi. In line 6) two elbows of 90 degrees are 2*0.75 instead of 2*1.5. The result in line 6) should be 3.5. So, in line 8) your total friction loss is 213.9 J/kg. Am I correct?
The friction loss for a regular 90 degrees threaded elbow is 1.5, therefore, for two elbows it is 2*1.5. The calculation shown in the video is correct!
thank you so much for the explanations, but why in Ef pipe length of 35 m, the D become 0,00291 m? is it the D or not? in the problem the D is 0,02291 m
Thank you for identifying the correction. In step 7, the value of D is incorrectly written as 0.00291, it should be 0.02291. The calculated value of 187.2 is correct.
Excellent explanation. Very concise and useful. Thanks.
Hello, Thanks for the video. I have 2 questions and 1 comment :)
1. In line 7) of your calculation (approx. 09:35 - :09:50): Why do you use a factor of 2 i.e. 2 x 0.0046 x ... x 35 /diameter. You are calculating the loss in the pipe which there is 1 off. (There are 2 bends, hence a factor of 2, OK)
2. In line 7) of your calculation (approx. 10:06): Why do you use 0.00291 m for the pipe diameter when you at the start says it is: 0.0291 m (a decade in difference).
3. Also, the friction factor of 0.0046 ...? Does such a smooth pipe exist? (The value is outside my Moody diagram).
In line 7, the factor "2" is part of the equation, please see the derivation. Ef =2 x f x u^2 x L/D
The denominator term for Diameter should be 0.02291. In fact, in the calculation, the correct diameter is used. The resulting value of 187.2 is correct. Thank you for noting this, I will make the correction in the video.
The friction factor of 0.0046 is correct. Please recheck the Moody diagram.
Hi. In line 6) two elbows of 90 degrees are 2*0.75 instead of 2*1.5. The result in line 6) should be 3.5. So, in line 8) your total friction loss is 213.9 J/kg. Am I correct?
The friction loss for a regular 90 degrees threaded elbow is 1.5, therefore, for two elbows it is 2*1.5. The calculation shown in the video is correct!
thank you so much for the explanations, but why in Ef pipe length of 35 m, the D become 0,00291 m? is it the D or not? in the problem the D is 0,02291 m
Thank you for identifying the correction. In step 7, the value of D is incorrectly written as 0.00291, it should be 0.02291. The calculated value of 187.2 is correct.