Precision Variable-Angle Inclined Wetted Plate
Stainless steel plate (length 1000 mm, width 200 mm) equipped with micrometer angle adjustment.
Chemical & Process Engineering / Falling Film Non-Newtonian Rheometry
FREE TO EXPLORELABORATORY 07 · CHEMICAL & PROCESS ENGINEERING
Falling Film Wetted-Wall Rheometry & Ostwald–de Waele Power-Law Fluid Kinetics
Measure surface velocity and liquid holdup of a non-Newtonian polymer solution flowing down an inclined wetted-wall flat plate, determine the flow behavior index n and consistency index K of the Ostwald–de Waele power-law model. Explore interactive transport phenomena, unit operations simulation, and chemical engineering telemetry.
TRANSPORT PHENOMENA · UNIT OPERATIONS · PROCESS CONTROL · REACTION ENGINEERING
Your virtual chemical and process engineering laboratory.
LOG FILM SURFACE VELOCITY LN(U_S)—
PROCESS & PILOT PLANT TELEMETRY
Ready to sample with Flow Rate Γ = 6.0 g/(s·cm).
Adjust Flow Rate Γ, then execute chemical process trial.
Chemical and process engineering telemetry is evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity transport phenomena and unit operations modeling.
Process engineering assumptions and boundary condition limits
The transport and thermodynamic models apply within the specified calibrated operating window (2.0 to 12.0 g/(s·cm)). Evaluated using a 0.50% aqueous sodium carboxymethylcellulose (CMC) solution descending an inclined plate (width W = 200 mm, inclination angle θ = 45°). Linearized logarithmic regression relates ln(u_s) to ln(Γ) to extract flow behavior index n = 0.60.
Process apparatus & industrial sensors.
Liquid Distribution Overflow Weir & Calming Box
Delivers uniform, crest-free laminar liquid film distribution across 200 mm plate width.
High-Speed Digital Video Particle Tracking System
Tracks reflective surface micro-tracers to determine surface velocity u_s with 0.1% accuracy.
Peristaltic Metering Circulation Pump
Delivers pulsation-free polymer liquid flow across mass rates Γ = 2 to 12 g/(s·cm).
Micrometer Needle Film Thickness Probe
Measures liquid film thickness δ at three down-plate stations with 5 μm precision.
Thermostatically Controlled Polymer Feed Reservoir
Maintains 0.50% CMC solution at 25.0 ± 0.1 °C with continuous low-shear agitation.
FOLLOW THE METHOD
A reason behind every step.
Measure surface velocity and liquid holdup of a non-Newtonian polymer solution flowing down an inclined wetted-wall flat plate, determine the flow behavior index n and consistency index K of the Ostwald–de Waele power-law model. Standardized parameter settings: 2.0, 4.0, 6.0, 8.0, 10.0, 12.0 g/(s·cm).
01
Plate Leveling & Angle Alignment
Set the wetted plate inclination angle to exactly θ = 45.0° using a digital inclinometer; verify horizontal transverse leveling.
02
Film Wetting & Equilibrium Establishment
Circulate polymer solution at moderate flow for 10 minutes to achieve complete, uniform surface wetting without dry patches or rivulets.
03
Initial Flow Rate Calibration
Adjust pump delivery until liquid flow rate per unit width Γ reaches 2.0 g/(s·cm); verify gravimetrically by timed effluent collection.
04
Surface Tracer Velocimetry
Inject tiny buoyant hydrophobic tracer flakes onto the film centerline and record passage time across a 500 mm measurement grid using high-speed video.
05
Flow Rate Progression
Increment flow rate Γ through 4.0, 6.0, 8.0, 10.0, and 12.0 g/(s·cm), logging film thickness δ and surface velocity u_s at each step.
06
Power-Law Rheological Regression
Compute ln(Γ) and ln(u_s) for each plateau, plot ln(u_s) versus ln(Γ), and extract the slope m to calculate flow behavior index n.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into chemical process engineering insight.
Points are your recorded observations. The solid regression line validates Falling Film Non-Newtonian Rheometry mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
ln(u_s) = m · ln(Γ) + c = 1.3500 · ln(Γ) + 0.1500
| # | Film Liquid Mass Flow Rate Γ (g/(s·cm)) | Log Film Surface Velocity ln(u_s) (ln(cm/s)) | Log liquid mass flow rate ln(Γ) (ln(g/(s·cm))) | Log surface velocity ln(u_s) (ln(cm/s)) | Remove |
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No readings yet. Execute a process trial and record it.
Calculate it yourself.
CHECK YOUR UNDERSTANDING
Explain what the process engineering metrics mean.
For an Ostwald–de Waele power-law fluid, shear-thinning (pseudoplastic) behavior corresponds to:
In a steady laminar falling liquid film, the shear stress τ_yx at the free liquid-gas interface equals:
For a Newtonian fluid (n = 1), the logarithmic slope m relating surface velocity to mass flow rate (ln u_s vs ln Γ) equals:
If the experimental slope m = 1.350, the corresponding power-law flow behavior index n is:
THEORY AND UNIT OPERATIONS CONTEXT
Process engineering background & physical principles.
Falling liquid films over solid surfaces are ubiquitous in chemical process operations, including wetted-wall gas absorbers, falling-film evaporators, trickle-bed reactors, and polymer devolatilizers. In many industrial applications—such as paints, biological fermentation broths, polymer melts, and starch slurries—the process liquid displays non-Newtonian shear-thinning (pseudoplastic) rheology, described by the Ostwald–de Waele power-law model: τ_yx = K · |du/dy|^n, where K is the consistency index and n < 1 is the dimensionless flow behavior index. When a thin liquid film descends steadily under gravity down a plane inclined at angle θ, a momentum balance yields a shear stress profile that varies linearly from zero at the free liquid-gas interface to maximum shear at the solid wall: τ_yx(y) = ρ g cos θ · (δ - y), where δ is film thickness. Integrating this stress distribution with the power-law constitutive equation provides analytical velocity profiles and links surface velocity u_s to mass flow rate per unit wetted width Γ via: u_s ∝ Γ^[(n+1)/n]. In this laboratory investigation, surface tracer velocimetry is performed on an aqueous carboxymethylcellulose (CMC) solution down a precision inclined wetted plate to measure surface velocity u_s vs flow rate Γ, evaluate rheological slope m = (n+1)/n, and determine the flow behavior index n.
ln(u_s) = m · ln(Γ) + c = 1.3500 · ln(Γ) + 0.1500
Evaluated using a 0.50% aqueous sodium carboxymethylcellulose (CMC) solution descending an inclined plate (width W = 200 mm, inclination angle θ = 45°). Linearized logarithmic regression relates ln(u_s) to ln(Γ) to extract flow behavior index n = 0.60.