The Journal of Non-Newtonian Fluid Mechanics regularlypublishes research on flowing soft matter systems. Articles in all areas of complex fluids are published, including polymer melts and solutions, suspensions, colloids, surfactant solutions, biological fluids, gels, liquid crystals and granular materials. Areas of interest involve flow problems relevant to microfluidics, nanofluidicsbiological and geophysical flows in addition to industrial processes.

NETZSCH Analyzing & Testing is proud to be involved in the latest publication on the RelaxationRelaxation은 고무에 일정한 변형률이 가해지면, 변형률을 유지하기 위해 필요한 힘은 일정하지는 않지만 시간에 따라 감소합니다. 이러한 특성을 ‘응력 완화’라고 부릅니다. 응력완화의 원인이 되는 과정은 물리적 또는 화학적 그리고 정상적인 조건 하에, 둘 다 동시에 일어날 수 있습니다. relaxation time of entangled Hydrolyzed Polyacrylamide (HPAM) solutions in flow.

HPAM is a type of water-soluble polymer commonly used in the oil and gas industry to enhance oil recovery. In connection to rheology and flow, HPAM is important because it can modify the flow behavior of fluids, particularly in porous media such as rock formations.

“In recent years, there have been an increasing number of studies of the flow of elastic polymer solutions. Much of this activity has been motivated by the realization of the importance of elastic turbulence, a purely elastic instability, in industrial applications. More recently, increased heat transfer has also been observed for solutions exhibiting elastic turbulence.

It is generally understood that for entangled viscoelastic polymer solutions, entanglement effects are significantly weakened under strong flow. In recent years, it has been observed that, despite quiescently being entangled at use concentrations, high molecular weight HPAM (hydrolyzed polyacrylamide) solutions are characterized by their Rouse time1 when transitioning to elastic turbulence in porous flow. Whereas this has been inferred, for these practically important solution polymers direct measurement of the apparent characteristic RelaxationRelaxation은 고무에 일정한 변형률이 가해지면, 변형률을 유지하기 위해 필요한 힘은 일정하지는 않지만 시간에 따라 감소합니다. 이러한 특성을 ‘응력 완화’라고 부릅니다. 응력완화의 원인이 되는 과정은 물리적 또는 화학적 그리고 정상적인 조건 하에, 둘 다 동시에 일어날 수 있습니다. relaxation time under shear has not been reported.

In this study, controlled-StressStress is defined as a level of force applied on a sample with a well-defined cross section. (Stress = force/area). Samples having a circular or rectangular cross section can be compressed or stretched. Elastic materials like rubber can be stretched up to 5 to 10 times their original length.stress parallel-superposition was used to assess the apparent characteristic RelaxationRelaxation은 고무에 일정한 변형률이 가해지면, 변형률을 유지하기 위해 필요한 힘은 일정하지는 않지만 시간에 따라 감소합니다. 이러한 특성을 ‘응력 완화’라고 부릅니다. 응력완화의 원인이 되는 과정은 물리적 또는 화학적 그리고 정상적인 조건 하에, 둘 다 동시에 일어날 수 있습니다. relaxation time as a function of steady background shear rate. The results coincide with a recently reported calculation using Rolie-poly and Rolie-double-poly models.”

Source: The relaxation time of entangled HPAM solutions in flow - ScienceDirect

1Rouse Relaxation Time - an overview | ScienceDirect Topics

NETZSCH Involved in this Publication

NETZSCH Analyzing & Testing, in person Dr. Shona Marsh (Application & Product Marketing Manager Rheology at NETZSCH A&T) has been involved in this latest rheology publication, in which the NETZSCH Kinexus ultra+ rotational rheometer is used to measure the effective characteristic time of a polymer solution under steady shearing using controlled-StressStress is defined as a level of force applied on a sample with a well-defined cross section. (Stress = force/area). Samples having a circular or rectangular cross section can be compressed or stretched. Elastic materials like rubber can be stretched up to 5 to 10 times their original length.stress parallel-superposition.

Read and download the publication by Enny Tran and Andrew Clarke as part as the Journal of Non-Newtonian Fluid Mechanics here: 

Photo: Dr. Andrew Clarke (Schlumberger Cambridge Research) and Dr. Shona Marsh (NETZSCH Analyzing & Testing)