Case study · Fluid dynamics & phase behavior

Characterizing shear-sensitive additives without sample degradation: a low-shear pressure drop test rig

For a major player in the energy industry, IRIAN Mecatronics designed and built a custom test rig to quantify the effectiveness of drag-reducing agents (DRAs). The system measures pressure drop reduction in turbulent flow (up to 50 bar [725 psi] and 70°C [158°F]) while preserving the integrity of the additives, which are highly sensitive to mechanical shear.

Client: A major player in the energy industry
Field: Oil & Gas / fluid dynamics
Technique: Pressure drop measurement / additive effectiveness

01 — The research question

How to measure the effect of a fragile product without the instrument skewing the results?

Many fluids and additives, from long-chain polymers to biological suspensions, are sensitive to mechanical stress. Characterizing their properties (viscosity, texture, effectiveness) is a challenge: the measurement instrument itself—with its pumps, valves, and bends—can shear and irreversibly degrade the sample, making the results useless. The difficulty lies in creating a test environment that replicates the conditions of interest without introducing parasitic stresses that destroy the sample.

Our client needed to quantify the performance of drag-reducing agents (DRAs) to optimize hydrocarbon transportation in pipelines. This required simulating turbulent flow at a high Reynolds number. However, standard laboratory test rigs, with their conventional components, would have destroyed the DRA polymer molecules by shearing them even before they entered the measurement section, making any evaluation impossible.

The challenge was to generate a high-Reynolds-number turbulent flow—which inherently creates high shear in the pipe—while protecting the shear-sensitive DRA molecules from degradation throughout the rest of the flow loop, particularly at the injection point.

02 — Our approach

Our approach: preserving the sample at every stage of the flow loop

The design of this test rig was driven by one critical requirement: ensuring that the only significant shear experienced by the DRA molecules occurs within the test tube during turbulent flow. Every component, from the injection system to the pressure taps, was selected or custom-designed to eliminate any parasitic mechanical stress.

Injecting the additive without alteration

To inject concentrations of a few ppm of a fragile product into a pressurized line, we designed a positive displacement system. Its fluid path eliminates all shear points (restrictions, sharp edges) typical of standard metering pumps. This ensures the additive is tested in its original state, guaranteeing reliable measurements.
Simulating pipeline flow in the lab

To simulate a long pipeline section in a compact space, the rig uses 6-meter test tubes coiled into spools. These columns are mounted on a removable and interchangeable heated support. This allows the user to quickly explore different velocity and shear conditions across several diameters, all within a compact, temperature-controlled custom test bench.
Designing a full-bore fluid circuit

To prevent any parasitic degradation from skewing the measurement, the entire circuit in contact with the mixture is designed with full-bore components. By avoiding standard valves and fittings that create restrictions, we ensure that the measured pressure drop is solely due to friction in the column, not to artifacts.
Measuring very low pressure drop with high accuracy

DRA performance is determined by a small pressure difference under a high static pressure (50 bar). We used a high-resolution differential pressure transducer with short, direct impulse lines. This provides the user with high-fidelity data, enabling precise and reliable quantification of the additive's effectiveness.

03 — Beyond this project

Does your project involve a shear-sensitive fluid?

Food & Beverage

Common challenge: Pumping and circulating fragile products (emulsions, sauces) without breaking down their texture.
What we would keep: The principle of a very low-shear circuit, with a syringe pump and full-bore valves, adapted with sanitary materials and fittings (316L stainless steel, tri-clamp).

Biotechnology / Pharma

Common challenge: Handling protein solutions or cell suspensions without denaturing molecules or lysing cells.
What we would keep: The design of the low-shear high-precision injection pump and the overall circuit layout, adapted for scale (e.g., microfluidics) and biocompatible materials.

Cosmetics

Common challenge: Manufacturing creams or gels whose properties depend on shear-sensitive colloidal structures.
What we would keep: The mastery of shear control throughout the process to guarantee final product consistency, adapting the design to meet cleanliness and chemical compatibility standards.

04 — Specifications

The values for this project. Every system is custom-built, so they adapt to your requirements.

Show specifications · 50 bar (725 psi) · 70°C (158°F) · 5,000 - 50,000

Technical specifications — Characterizing shear-sensitive additives without sample degradation: a low-shear pressure drop test rig
Maximum operating pressure	50 bar (725 psi)
Maximum operating temperature	70°C (158°F)
Target Reynolds number range	5,000 - 50,000
DRA injection flow rate	0.002 to 2.5 cm³/min
Test column diameters (OD)	1/8", 1/4", 1/2"
Test column length	6 m (approx. 20 ft)
Differential pressure measurement uncertainty	±0.035%

IRIAN Mecatronics designs and builds custom high-pressure, high-temperature equipment for research laboratories, technical centres and industry.

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05 — FAQ

Frequently asked questions

Can this low-shear test rig be adapted for food or pharmaceutical fluids?

Yes, the design principle is directly transferable. The adaptation would mainly involve changing the wetted materials (e.g., 316L stainless steel, PEEK, with FDA/EC 1935/2004 compliance), integrating sanitary fittings (e.g., tri-clamp), and designing the circuit to facilitate clean-in-place (CIP) procedures. The core of the solution—the very low-shear injection and circulation system—would remain the same.

Is it possible to perform pressure drop tests at higher pressures and temperatures?

Yes, designing high-pressure, high-temperature equipment is our core business. The low-shear circuit principle remains valid, but all components (tubing, valves, sensors) would be selected to withstand the target pressure and temperature, using appropriate materials (nickel alloys, etc.). Our expertise includes designing custom HPHT reactors and cells for much more severe conditions.

Can other online measurements, such as viscometry, be integrated into this rig?

Absolutely. The modular design of our equipment allows for it. We could integrate a viscometer or another online sensor, provided it is also designed to avoid generating parasitic shear that would interfere with the primary measurement. The automation and control software would be adapted to acquire and log this new data.

How do you ensure traceability and repeatability for qualification studies?

Traceability is ensured by our automation and quality management system. The rig is controlled by a PLC that runs defined test sequences and continuously records all parameters (pressures, temperature, flow rates). As an ISO 9001 certified company, we provide comprehensive documentation, including Factory Acceptance Test (FAT) protocols and calibration certificates for all sensors.

Is your measurement instrument degrading your product and skewing your results?

Describe your shear constraints and target test conditions. Our engineering team will analyze your project's feasibility and get back to you with a proposed approach.

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