Agitator Designs by Wahal for Gas, Liquid & Solid Mixing (With CFD Validation)

Industrial mixing rarely involves just one phase. A reactor may need to disperse gas and suspend a catalyst. A blending tank may need to combine two liquids of different viscosities without shearing them. Each phase combination needs a different agitator.

Wahal Engineers, founded in the 1980s, designs its agitator range around this reality — with distinct impellers for gas-liquid, liquid-liquid, and solid-liquid duties, validated using CFD (Computational Fluid Dynamics) before fabrication.

The 3 Core Mixing Categories

• Gas-liquid mixing — dispersing gas into liquid (aeration, fermentation, hydrogenation)
• Liquid-liquid mixing — blending liquids of different viscosity/density (emulsification, dilution)
• Solid-liquid mixing — suspending or dissolving solids (slurries, crystallization, powder wetting)

Using the wrong impeller for the phase mix causes common failures:

• Flooded impellers that can’t disperse gas
• Dead zones where solids settle and cake
• Under-mixed batches, longer cycle times, wasted energy

Agitators for Gas-Liquid Mixing

Goal: shear gas into fine bubbles and hold them in the liquid long enough for mass transfer, without flooding.

Common impeller types:

• Rushton (disc) turbines — flat radial blades on a disc; strong gas-handling capacity, industry standard for fermenters and reactors
• Hollow/concave blade turbines — streamlined version of Rushton design; lower power draw, better flood resistance
• Sparge ring feed — gas released directly beneath the impeller for finer bubble breakup

Agitators for Liquid-Liquid Mixing

Viscosity range dictates impeller choice:

Also common:

• Scraper agitators — clear jacketed vessel walls for uniform heat transfer
• Baffles — break vortex flow, improve turnover

Agitators for Solid-Liquid Mixing

• Pitched-blade / hydrofoil turbines — axial, down-pumping flow lifts settled solids off the base; standard for suspension duty.

What CFD adds:

• Flow visualization — reveals dead zones and velocity patterns in the actual vessel, not a generic model
• Power & torque prediction — estimates shaft loads using real fluid properties before fabrication
• Solid suspension verification — predicts particle concentration profiles across the vessel, not just near the impeller
• Gas dispersion modeling — multiphase CFD estimates bubble distribution, gas hold-up, and flooding risk
• Fewer pilot trials — virtual testing of geometry/impeller changes cuts physical trial-and-error before full-scale build

Wahal Engineers pairs CFD analysis with pilot-scale testing to validate impeller selection, vessel geometry, and baffle placement — especially useful for high-shear mixers and multiphase systems where empirical rules alone leave too much uncertainty.

Agitator Selection Checklist

Before specifying an agitator, define:

• ✅ Mixing objective — blending, suspension, gas dispersion, heat transfer, or combined
• ✅ Fluid properties — viscosity, density, non-Newtonian behavior, shear sensitivity
• ✅ Solids content — particle size, settling velocity, abrasiveness
• ✅ Vessel geometry — diameter, height-to-diameter ratio, internals (coils, baffles, dip tubes)
• ✅ Operating conditions — temperature, pressure, sterility, hazardous area rating
• ✅ Mounting type — top-entry, side-entry, or bottom-entry
• ✅ Materials & seals — chemical compatibility, corrosion/abrasion resistance

Combining phase-specific impeller design with CFD validation — the approach used by Wahal Engineers — shortens the path from process requirement to a reliably performing, correctly sized agitator.

We also manufacture:

side entry agitator

side entry tank mixers