Research Centre

Our links with Universities in the UK and overseas have developed into an extensive and valuable network for research, providing cutting-edge technology support to CALGAVIN and our clients.

CALGAVIN welcomes links with research groups, thermal engineers working in the field of thermal process enhancement and optimisation.

Research Projects

1. Single phase flow research

2. Two phase flow research

3. Boiling  – vaporisation

4. Fouling mitigation

1. Single Phase Flow – testing

A state-of-the-art single phase test facility has been running for a number of years in CALGAVIN’s thermal laboratory. This highly accurate test rig is producing valuable data to enhance the scope and accuracy of performance predictions, subsequently incorporated in the hiTRAN SP design programme. The facility is used to optimise hiTRAN Element geometry and test new types of enhancement for special purposes.

Technical Data

  • Length of measurement section – 3 metres
  • Tube geometries from 10mm to 32mm ID
  • Viscosities from 0.1 mPas to about 1Pas
  • Reynolds Numbers ranging from 1 to 200000
  • Maximum heat duty – 18kw
  • Average heat balance error during experiments – less than 3%
  • Fully integrated control and data acquisition

Single-phase test rig (CALGAVIN laboratory)

Acknowledgment for support: University of Birmingham

2. Two phase flow research

Two-phase flow pilot plant

Condensation

Pure component condensation, based on refrigerant 113 in vertical tube, provided data giving 40-60% increased heat transfer, dependant on geometry.

Acknowledgment for support: Queen Mary’s College, London

Reflux condensation research provided information on heat transfer and pressure loss together with the impact of flooding and affects caused by processing multi-component mixtures.

Results: For multicomponent mixtures (Methanol / Water) experiments and simulations show a substantial increase in interfacial mixing, resulting in much improved heat & mass transfer. In addition it is shown that the use of hiTRAN Elements can be beneficial with respect to the onset of flooding.

Acknowledgment for support: Umist, Manchester

3. Boiling – Vapourisation

Thermosyphon reboiler studies

Thermosiphon Reboiling

Research focused on performance benefits provided by:

  • smaller temperature differences between heating side and product side
  • operating with higher viscosity substances
  • operating with lower absolute pressure
  • reducing sub-cooled length in operation with viscous fluids and under vacuum

Results show that operational stability is much improved over a wide range of operating conditions. hiTRAN Elements were found to control fluctuations in circulation rate, usually found with plain tube arrangements. Improved heat transfer was observed even at lower circulation rates and within acceptable operating pressure-loss. Research continues to identify underlying mechanisms in different flow sections.

Acknowledgement for support: University of Braunschweig, Germany

Falling film studies

Falling Film Evaporation

Falling film evaporators are typically characterised by a short product residence time. When viscous liquids (higher Prandl number) are being processed, tube-side heat transfer is heavily controlled by the resistance of the laminar-wavy fluid film. hiTRAN Matrix Elements modify hydro-dynamics to provide well distributed liquid over the whole tube circumference, combating mal-distribution.

Experiments show that fluid entering the tube in the centre (extreme mal-distribution) is evenly distributed after just a few diameters. The elements also provide a support structure whereby film thickness is increased. The mechanism also provides for the removal of the stagnant layer from the wall, effecting good back mixing between wall film and bulk film, resulting in a narrower residence time distribution under laminar and laminar-wavy conditions.

Results over the whole range of tests showed a substantial increase in heat transfer of up to 80%.

Acknowledgement for support: University of Bremen, Germany

4. Fouling mitigation studies

Hydrocarbon chemical reaction fouling  – Crude oil tests

Reaction rates are heavily dependant on temperature, in general described with Arrhenius approach. Reaction rates are a function of the residence time that the process liquid is exposed to temperatures higher than the cracking temperature of the fluid.

Experiments used light Arabian crude, Watson factor = 11.4. Parallel tubes, plain (control) and enhanced (hiTRAN Elements) were tested under similar conditions. Substantial and sustained fouling reduction was measured.

Fouling factor

Advantageous effects:

  • Lower tube-wall temperature for same duty
  • Reduction in fluid volume which is heated above bulk temperature
  • Reduction in wall fluid residence time
  • Suppression of nucleation at the surface
  • Increased shear rate at the wall (higher removal rate)

Acknowledgement for support: University of Bath, UK

Particulate fouling

With increased wall shear and fluid mixing generated by the annular flow mechanism, hiTRAN Elements provide a high level of turbulence that mitigates particle deposition.

In laboratory tests, a laser-based method of measurement and time-lapsed photography was used to quantify the rate of sedimentation and the thickness.

Experiments using 50 micron particles (particle density 2500kg/m3) in water glycerol suspension was tested over a range of Reynolds Numbers. Vortices behind the wire loops cause turbulent mixing, resulting in the rate of particle removal being significantly higher than the rate of deposition. Even at low velocity particles remain suspended.

Photographic Evaluation of hydro-dynamics
Talcum as suspension particles, 40 to 60 microns, 2500kg/m3
Constant Re no. of 750

Photographic evaluation of particles in flow

  • High shear rate at the wall causes homogeneous distribution of particles
  • Vortexes behind the wire loops causes high liquid mixing

Acknowledgement for support: University of Edinburgh, Scotland