## How to Calculate and Solve for Relative Apparent Viscosity (for Concentrated suspension) | Rheology

The image above represents relative apparent viscosity (for concentrated suspension).

To compute for relative apparent viscosity (for concentrated suspension), three essential parameters are needed and these parameters are Intrinsic Viscosity (ηi), Solid Landing (φ) and Maximum Solid Landing (φm).

The formula for calculating relative apparent viscosity (for concentrated suspension):

ηra = (1 – φ / φm)-(ηim

Where:

ηra = Relative Apparent Viscosity
ηi = Intrinsic Viscosity
φ = Solid Landing
φm = Maximum Solid Landing

Let’s solve an example;
Find the relative apparent viscosity when the intrinsic viscosity is 20, the solid landing is 32 and the maximum solid landing is 12.

This implies that;

ηi = Intrinsic Viscosity = 20
φ = Solid Landing = 32
φm = Maximum Solid Landing = 12

ηra = (1 – φ / φm)-(ηim
ηra = (1 – 32 / 12)-(20) x 12
ηra = (1 – 2.66)-240
ηra = (-1.66)-240
ηra = 5.705e-54

Therefore, the relative apparent viscosity (for concentrated suspension) is 5.705e-54.

## How to Calculate and Solve for Sedimentation of Concentrated Suspension | Rheology

The image above represents sedimentation of concentrated suspension.

To compute for sedimentation of concentrated suspension, five essential parameters are needed and these parameters are Change in Density between the Dispersed and Continuous Phase of the Suspension (ΔP), Acceleration due to Gravity (g), Particle Radius (a), Viscosity of Continuous Phase (η) and Solid Landing (φ).

The formula for calculating sedimentation of concentrated suspension:

v = 2ΔPga2 / (1 – φ)5 ± 0.25

Where:

v = Sedimentation of Concentrated Suspension
ΔP = Change in Density between the Dispersed and Continuous Phase of the Suspension
g = Acceleration due to Gravity
η = Viscosity of Continuous Phase
φ = Solid Landing

Let’s solve an example;
Find the sedimentation of concentrated suspension when the change in density between the dispersed and continuous phase of the suspension is 20, the acceleration due to gravity is 12, the particle radius is 32, the viscosity of continuous phase is 14 and the solid landing is 0.

This implies that;

ΔP = Change in Density between the Dispersed and Continuous Phase of the Suspension = 20
g = Acceleration due to Gravity = 12
a = Particle Radius = 32
η = Viscosity of Continuous Phase = 14
φ = Solid Landing = 0

v = 2ΔPga2 / (1 – φ)5 ± 0.25
v = 2 x 20 x 12 x 322 / 9 x 14 x (1 – 0)5 + 0.25
v = 2 x 20 x 12 x 1024 / 126 x (1)5.25
v = 491520 / 126 x 1
v = 3900.95 x 1
v = 3900.95

Therefore, the sedimentation of concentrated suspension is 3900.95.

## How to Calculate and Solve for Einsten Relative Apparent Viscosity (for Dilute System or Suspension) | Rheology

The image above represents einstein relative apparent viscosity.

To compute for einstein relative apparent viscosity, one essential parameter is needed and these parameter is Solid Landing (φ).

The formula for calculating einstein relative apparent viscosity:

ηra = 1 + 25φ

Where:

ηra = Einstein Relative Apparent Viscosity
φ = Solid Landing

Let’s solve an example;
Find the einstein relative apparent viscosity when the solid landing is 24.

This implies that;

φ = Solid Landing = 24

ηra = 1 + 25φ
ηra = 1 + 25 x 24
ηra = 1 + 600
ηra = 601

Therefore, the einstein relative apparent viscosity is 601.