Ormiston Wire produces bespoke mini heat exchange

The transfer of heat in engineering systems requires robust, carefully designed components that can be easily installed and maintain their performance over a long operating lifespan. The company's wire turbulators have many advantages over Fin or Spiral sheet metal types for, as well as benefiting immensely from Ormiston Wire's own looped-spiral design. They can be adapted or even custom-built to suit a customer's particular specifications.

Ormiston Wire was recently approached by a new customer seeking to solve a heat transfer problem involving a piece of their machinery. The company immediately realised that it required an approach outside their normal size range.

However, drawing on their extensive expertise and experience enabled them to design, develop and manufacture a bespoke mini wire-wound turbulator. With a series of loop turns, this had an outside diameter of just 3mm, as compared with the slightly larger sizes available in the existing ranges of turbulators.

This miniature spiral wire wound turbulator performed well in initial trials and has since undergone further series of evaluation tests. Even as standard, the company's turbulators are available in a large variety of forms. Lengths ranging from 15cm up to 3m can be provided in diameters varying between 6.35mm and 32mm. They also come in a choice of metals suited to the application, including galvanised mild steel, stainless steel, copper and Monel metal.

Moreover, the loop density of the turbulator can be varied to suit the liquid or gas flowing through a tube, optimising heat transfer and pressure drop. For longer tube lengths, individual turbulators can be simply and quickly joined together. This economises on the length, diameter or number of tubes required per unit and allows flow pumps to be kept to a minimum size. The efficiency of the turbulators is further enhanced by the fact that they do not need to be fixed in the tubes, the wires themselves gripping quite tightly and rarely moving within a normal flow of liquid or gas.

Typically, when fluid flows through a tube frictional drag creates a slower moving boundary layer at the tube wall. When the tube wall is cooler than the fluid flowing through the tube, then viscosity at the wall is greater than that at the centre of the tube, reinforcing the boundary layer. This provides a resistance to heat transfer, which in turn restricts performance.

Ormiston spiral wire wound turbulators are designed to regularly disrupt this cool boundary layer and re-mix this disrupted fluid with the warmer bulk fluid towards the centre of the tube. This reduces the temperature difference across the tube bore, minimising the boundary layer resistance.

Due to their remarkable versatility, Ormiston spiral wire wound turbulators have proved their value in many applications over the past 50 years, and the company is constantly discovering new opportunities for engineers to explore in heat exchange technology. For further information go to www.ormiston-wire.co.uk.