Additively Manufactured Ring-Type Thermal Sensor for In-Pipe Flow Monitoring in a Marine Engineering Context: Design...

Area of Science:

• Additive Manufacturing
• Materials Science
• Sensor Technology
• Fluid Dynamics

Background:

• In-pipe flow monitoring is crucial for industrial processes and vessel operations.
• Traditional sensors can be costly and complex to install.
• Additive manufacturing offers potential for low-cost, integrated sensor solutions.

Purpose of the Study:

• To design, fabricate, and characterize a novel ring-type thermal airflow sensor using Fused Deposition Modelling (FDM).
• To explore the design evolution for optimized thermal localization and reduced power consumption.
• To demonstrate the feasibility of monolithic integration of sensors into 3D-printed structures.

Main Methods:

• Utilized Fused Deposition Modelling (FDM) with a Carbon Nanotube (CNT)-enriched Polylactic Acid (PLA) composite.
• Conducted Constant-Current (CC) Joule heating experiments to characterize sensor elements.
• Employed Finite Element Method (FEM) modeling for design optimization and performance validation.
• Integrated the sensor directly into a 3D-printed pipe segment for monolithic construction.

Main Results:

• Achieved thermal localization at approximately 26% lower power after geometry optimization.
• The final monolithic sensor showed a resistance decrease with increasing airflow (ΔR ≈ 117 Ω over 0-4 m/s).
• Demonstrated rapid response and partial recovery of resistance upon flow interruption.
• FEM simulations validated experimental results and clarified convective cooling effects.

Conclusions:

• The additively manufactured ring-type thermal airflow sensor is a low-cost, simple, and effective solution for in-pipe flow monitoring.
• The monolithic design, enabled by FDM, eliminates interconnections and allows for integrated structural and sensing functionality.
• The technology shows significant potential for condition-based maintenance systems in industrial sectors and maritime applications.