Shear rate is defined as the flow velocity gradient in the direction perpendicular to the flow direction (ScienceDirect) and is a key parameter when measuring viscosity of both Newtonian and non-Newtonian fluids. Knowing and understanding shear rates enable you to explore various factors on how your sample behaves and can determine the fate of your product performance (RheoSense).
All RheoSense rectangular slit method viscometers (USP chapter 914) are powered by our patented VROC® (Viscometer-Rheometer-on-a-Chip) technology, combining microfluidic and MEMS (Micro-Electro-Mechanical Systems) technologies to measure dynamic viscosity over a wide dynamic range of operation. VROC viscometers control the flow rate of your sample and measures pressure to calculate shear rate and stress. While all RheoSense viscometers are powered by the same VROC technology, they all serve very different purposes and have unique specifications and applications. Each VROC powered viscometers is supported by its own software, helping to automate measurements, simplify protocols creation, and to organize and analyze your data.
The specifications and testing capabilities of each VROC powered viscometer are distinguished even further by the different chips you can use for each instrument! Our different chips allow:
When it comes to measuring your samples, the channel depth of the instrument you use will determine your shear rate range. The different VROC chips that pair with each instrument have different pressure ranges they can withstand and allow users to measure a range different flow channels. There are 4 different chip types for the m-VROC and VROC initium viscometers (A, B, C, E).
There are 3 different chip types for the microVISC (A, B, C). These chips share the same viscosity ranges as the m-VROC and initium chips, however they all have a maximum shear rate of 5,800 1/s due to the shear rate measurements capabilities of the microVISC instrument.
VROC chips need viscosity and shear rate in balance. The A05 chip is ideal for low viscosity fluids and intrinsic viscosity measurements whereas the E02 chip is ideal for high viscosity & high shear rates.
*Shear rate max could potentially vary depending on sample
If you want to learn more about selecting the right instrument or chip for your samples, contact us to speak with one of our rheology experts today!
Written by: Eden Reid, RheoSense Senior Marketing Associate