Chemical and Biomolecular Engineering

Official blog of the Lehigh University Chemical Engineers

Pressure Drop Experiment-Fluid Mechanics

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In my Fluid Mechanics class, we had to complete a lab, in order to apply the concepts we learn in class to a real world situation.

In this lab, we wanted to study the pressure drop in a pipe to see that pipes in real world conditions do not behave like pipes in textbook problems. The pipe we used in the lab had a pressure drop that is affected by geometry, flow characteristics and surface roughness. In real conditions, we use the modified Bernoulli’s equation which takes into account total head loss. Once we have the pressure drops corresponding to different flow rates, we calculated the Reynold’s number and relative roughness and use these values and a Moody diagram to find the theoretical friction factor of each point. We will observed discrepancies between the experimental and theoretical values. We also changed the pump frequency and flow rates to obtain pressure drops and will study how pump frequency affects the results.

We varied the water flow rate in a pipe (96” long with .5” diameter) from .3-6 gallons per minute using rotometers and obtained the corresponding pressure drops using pressure taps (Part 1). For each point we calculated the friction factor and then, we used the Reynold’s number and relative roughness calculated to find the theoretical friction factor for each point using a Moody diagram. In order to evaluate the pump performance, we used a 2 HP variable speed centrifugal pump and set it 60 HZ (Part 2) and varied the flow rate using a large rotometer. We then recorded the voltage, current of power to pump and the outlet pressure from the pressure gage. We repeated this with the pump set to 30 HZ (Part 3). We had 5 flow rates and corresponding pressure drops for each part of the three parts of the lab. For each frequency, we plotted a pump curve (Pressure drop vs. Flow rate) and Pump efficiency vs. Flow rate.

This was a great opportunity to see the concepts we learn in class being applied to real situations. It was also a chance to become more familiar with the IMBT lab which hosts the Advanced Technology for Large Structural Systems (ATLSS) Engineering Research Center and the Energy Research Center.



Author: luniki15

Hi! I'm Nicolette Drescher. I am from York, Pennsylvania which is 2 hours west of Lehigh. I am majoring in Chemical Engineering. On campus, I am involved in various organizations. I am co-chair of the mission committee for the club Colleges Against Cancer. I am in Phi Sigma Pi, a national honor fraternity. I am also a member of the Society of Women Engineers, American Women's Medical Association and the Asian Cultural Society. I also just joined the Lehigh University Medical Services club as a certified PA EMT.

One thought on “Pressure Drop Experiment-Fluid Mechanics

  1. Nic blog thank’s sharing. Atico Export are the manufacturer of fluid mechanic lab equipment supplier and exporter in india,

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