Problem with pressure drop in pipeline

[discreet544]

Hi Folks;

As we all knew, and I used to experimentally observe it, as the temperature of water increases, pressure drop through pipeline (kPa/m) decreases. Now, I am getting the opposite, while the results are so consistent and reproducible ! As the water temperature increases, pressure drop increases too ! I have calibrated the pressure transducers, and those look fine. Any guess ? Has anybody seen such a situation ?

Also, as we all knew again, with decreasing velocity, friction factor increases (remember Moody diagram). Now for my case, I am getting decreasing trend for temperature range of 20 to 30, while the trend is increasing for above 30 !

I am running water in a 2" closed-loop pipeline of 46 m length, with a magnetic flow meter and digital pressure transducers.

Thanks;

 

[Navin A S]

</code>The reason for this behavior could be due to the fact that as the temperature of water increases, the viscosity of the water also increases, leading to an increase in the friction losses. This additional friction loss would be the cause of the increase in pressure drop.As far as the second observation is concerned, the reason could be due to the fact that at higher temperatures, the water molecules move faster and can cause turbulence in the fluid, leading to an increase in the friction losses. This could lead to an increase in the friction factor as well. It would be helpful if you could provide more details about the water flow rate, the type of pipe, etc. so that a more accurate explanation can be provided.