Abstract
Abstract
Highlights
Most energy systems rely on fluids to transfer heat from one device to another to facilitate power generation, provision of heating or production of chemicals
Buoyancy resulting from the lightening of the fluid close to the heated wall can provide a force that partially or fully drives the flow, referred to as mixed or natural convection, respectively
In this work, we are interested in whether a flow is turbulent or laminar under certain heating conditions and when a turbulent flow may be laminarised or vice versa under the influence of buoyancy. We address this question for a vertically heated pipe, initially in the dynamical systems context through linear stability and by investigating how travelling wave solutions are affected by the buoyancy force
Summary
Most energy systems rely on fluids to transfer heat from one device to another to facilitate power generation, provision of heating or production of chemicals. Flows are often forced through channels or arrays of pipes taking heat away from the surfaces. For example, the reactions occur within the fuel pins, which are cooled by flow of coolant through the channels formed by arrays of fuel pins to maintain their temperature within a specific limit as well as transferring energy to the steam generators. Buoyancy resulting from the lightening of the fluid close to the heated wall can provide a force that partially or fully drives the flow, referred to as mixed or natural convection, respectively. When heat flux is very high, we can have a ‘supernatural’ state of flow, where the buoyancy is sufficiently strong that a reversed pressure gradient may be necessary to limit or maintain a constant volume flux. Under certain conditions (e.g. the Boussinesq approximation) an upward heated flow may be considered equivalent to a downward flow cooled at the boundary (Appendix A)
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