CORRUGATED TUBE HEAT EXCHANGERS ( FOOD / PHARMA / CHEMICAL)

The development of corrugated tubes represents perhaps the most exciting advance in heat transfer technology. It has long been accepted that if you agitate a hot liquid it cools faster since the shaking produces turbulence, which enhances the heat transfer from the liquid to the air. HRSFUNKE developed heat transfer enhancing corrugated tubes to achieve a similar result by creating turbulence in the media without using any mechanical shaking. The shallow deformation of the corrugated tube causes the boundary layer to be disrupted without too large a reduction in the flow area and, providing the working diameters are chosen carefully, it does not prevent the free passage of particles or pieces or allow even the most viscous of fluids to bridge adjacent corrugations. Enhanced turbulence created by corrugation results in a higher partial heat transfer coefficient (a), by increasing the Nusselt Number.

Plain tubes offer the best geometry to withstand pressure but the worst for heat transfer due to the rapid build-up of the boundary layer. Plates in a plate heat exchanger induce local turbulence to increase heat transfer coefficient but are limited in terms of operating pressures and temperatures due to the elastomer gaskets. Also, the relatively narrow gap limits their use to fluids without large fibres and particulates. Corrugated tubes take the best features of both the plain tube and the plate heat exchanger.


pharma chemical and food shell and tube heat exchangers parts hrsfunke

TECHNOLOGY
Corrugated tube is produced by indenting a plain tube with a spiral pattern. This leads to different types of flow - spirals in the core and eddies at the periphery.

Schematic chemical and food shell and tube heat exchangers hrsfunke

The helical flow ensures that the fluid particles are alternatively close to the tube wall and then in the main flow. Between the helical impressions, around the circumference of the tube, a secondary flow, typically in the form of eddies, occurs. The flow ensures that the rate of decrease in boundary layer resistance exceeds the rate of increase in pressure loss ie high heat transfer coefficients with minimum increase in pressure drop.

Drawing chemical and food shell and tube heat exchangers hrsfunke

ADVANTAGES
The increase in heat transfer coefficient brings the temperature of the tube wall closer to the temperature of the bulk fluid on the tube. The deformation of the corrugated tube needs to be shallow enough to influence the flow (Fig. A) and thus the heat transfers (Fig. B). To ensure that the heat transfer is improved by the corrugation, the flow must be influenced within the heat conduction layer. Hydrodynamic thermal boundary layer corrugated tube shell and tube heat exchangers have many benefits and advantages over comparable smooth tube versions.

pharma chemical and food shell and tube heat exchangers hrsfunke

Clients and Specifiers

capricole construction
wsp
jumeriah
masafi
wasl properties
command of militar work
almara
saudi binladin group
aecom
dssr