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Single Phase Overview

When fluid flows through an empty tube, the fluid nearest the wall is subjected to frictional drag, which has the effect of slowing it down creating a laminar boundary layer.

For very low mass flows or viscous flows, this can lead to laminar flow throughout the tube, in which heat transfer is dominated by conduction, limiting heat transfer rate. It is essential to also understand in turbulent flow conditions (higher mass flows) the heat transfer is still controlled by the boundary layer.

By installing hiTRAN® Thermal Systems in the tube, the laminar boundary layer will be disrupted, creating additional fluid shear and radial mixing of fluid into the bulk. In laminar flow, this augments the conductive heat transfer, thereby significantly increasing performance. Even in turbulent regimes the boundary layer disruption is still effective in increasing heat dissipation.

Features & Benefits

High efficiency in laminar and to transition flow regimes

Heat transfer increases are up to 16 times in laminar flow, up to 12 times in transitional flow and over 4 times in turbulent flow.

Predictable performance

Performance is proportional in transition flow, avoiding the controllability issues experienced in empty tube transition flow.

Increase in duty within pressure drop limits

With greater frictional resistance with hiTRAN, increased heat transfer in laminar flow enables designs to operate at higher heat transfer at lower or equivalent pressure loss.

Customer-designed product

Design variability allows full optimisation based on application parameters and requirements using our unique hiTRAN®.SP algorithm.

New or Retrofit?

hiTRAN Thermal Systems can be applied for newly designed exchangers and help debottleneck exchangers in the field, installed in situ.

How it works

Fluid flow through empty tubes does not have the ideal conditions for heat transfer in laminar or transitional flow..
The image on the left shows fluid flowing in a glass tube with blue and red dye injected at the wall. Frictional drag at the wall and viscous shear forces within the fluid limits the heat transfer mechanism to conduction. Little or no mixing occurs between fluid layers.
This image shows a hiTRAN Thermal System changing the hydrodynamics within the tube. Flow disruption of the dye, created by the matrix at the wall causes shear stress and mixing resulting in a much higher rate of heat transfer.
Particle Image Velocimetry (PIV) charts comparing empty and hiTRAN enhanced tubes
The empty tube PIV chart shows particles in flowing fluid tracked by a laser providing different colour velocity vectors. The scale U/Umax shows red vector arrows (highest velocity) at the centre, reducing to blue vector arrows (zero velocity) and inefficient heat transfer, at the wall.
This chart gives detail from the PIV 3mm downstream of a hiTRAN Thermal System. Red vectors (high velocity) and blue vectors (low velocity) are now in opposite positions to the empty tube. hiTRAN creates an annular pseudoturbulent regime resulting in substantially higher heat transfer.