Answered step by step
Verified Expert Solution
Question
1 Approved Answer
A batch reactor is stirred by an impeller. The quality of mixing is mostly determined by the stirring power W , which is the rate
A batch reactor is stirred by an impeller. The quality of mixing is mostly determined by the stirring power W which is the rate at which work is done by the liquid within the reactor by the impeller. Stirring power is affected by the diameter D and rotational speed N revolutionss of the impeller, rho and mu of the liquid, and sometimes gravity g
The company you work for is planning on installing a batch reactor mixed by a m diameter impeller. Before integrating the reactor into the chemical process, engineers would like to know the stirring power at a given rotation rate. Therefore, you are tasked with building a pilot mixer at th scale. The reaction mixture is an aqueous solution whose density and viscosity can be taken to the same as that of water at deg C so you use roomtemperature water in your pilotscale mixer as well.
a Find a set of dimensionless Pi s that fully describes this system. Identify any known and named dimensionless groups that each Pi corresponds to
b If using deg C water in both the fullscale and pilotscale mixer, is it possible to find a rotation rate Nf of the fullscale mixer that would make it completely similar to the pilotscale mixer at rotationrate Np Show your work proving that this is or is not possible.
c In the case of stirred tank reactors, gravitational effects can sometimes be assumed negligible. If that assumption is reasonable for our system, which Pi can now be neglected?
d At an impeller rotation rate of s you find the pilotscale mixer to draw kW of power. Assuming gravitational effects to be negligible, find the rotation rate Nf needed to make the fullscale mixer completely similar to the pilotscale mixer at s
e Estimate the power draw of the fullscale mixer at the rotation rate calculated in part d
Step by Step Solution
There are 3 Steps involved in it
Step: 1
Get Instant Access to Expert-Tailored Solutions
See step-by-step solutions with expert insights and AI powered tools for academic success
Step: 2
Step: 3
Ace Your Homework with AI
Get the answers you need in no time with our AI-driven, step-by-step assistance
Get Started