Visualisation and measurement of a laminar boundary layer on the surface of an isothermal section-triangular roof

Natural convection in air over a heated section-triangular roof with a fixed aspect ratio of 0.1 is experimentally investigated. The development of the flow over the roof subject to a range of temperatures is measured by digital interferometry and thermocouples. The experiments present distinct images of the thermal boundary layer, which changes from a quasi-steady to an unsteady state as the surface temperature of the triangular roof increases. Contrary to numerical simulations previously published, the observed flow becomes unsteady, which is very likely influenced by uncontrolled perturbations at the critical Rayleigh number where a pitchfork bifurcation of a steady flow is theoretically expected.

Investigation of thermodiffusion phenomenon under influence of vibration using image processing approach

Thermodiffusion is the appearance of concentration gradient in a mixture when subjected to a temperature gradient. Thermodiffusion or Soret effect plays an important role in the underground reservoir distribution. Consequently, a majority of petroleum research is focused on understanding this phenomenon. There are may experimental measurements of thermodiffusion. However, measurements conducted in a microgravity environment minimize the effect of gravity and leads to accurate results. This study demonstrates the influence of vibration on thermodiffusion measurement in a microgravity environment. The aim is to show how the variation of certain parameters such as the frequency and amplitude of translational vibration as well as the temperature would impact the composition of components in the mixture of Water-Isopropanol. The Fast Fourier Transform image processing technique is used to analyse the data obtained from optical digital interferometry. Moreover, two sets of experimental runs with negative and positive Soret coefficients are tested. The analysis shows the maximum separation of components for the case without any forced vibration. Furthermore, it is shown the increase in Rayleigh number corresponds to decrease in separation of components.

Investigation of thermodiffusion phenomenon under influence of vibration using image processing approach

Thermodiffusion is the appearance of concentration gradient in a mixture when subjected to a temperature gradient. Thermodiffusion or Soret effect plays an important role in the underground reservoir distribution. Consequently, a majority of petroleum research is focused on understanding this phenomenon. There are may experimental measurements of thermodiffusion. However, measurements conducted in a microgravity environment minimize the effect of gravity and leads to accurate results. This study demonstrates the influence of vibration on thermodiffusion measurement in a microgravity environment. The aim is to show how the variation of certain parameters such as the frequency and amplitude of translational vibration as well as the temperature would impact the composition of components in the mixture of Water-Isopropanol. The Fast Fourier Transform image processing technique is used to analyse the data obtained from optical digital interferometry. Moreover, two sets of experimental runs with negative and positive Soret coefficients are tested. The analysis shows the maximum separation of components for the case without any forced vibration. Furthermore, it is shown the increase in Rayleigh number corresponds to decrease in separation of components.

Ground measurements of dcmix 4 project Fullerene based nanofluid

This work presents first on ground measurements of DCMIX 4 project ternary nanofluid Fullerene, 1,2,3,4-tetrahydronaphtalene and Toluene. Transport properties have been measured by Thermogravitational, Optical Digital Interferometry and Optical Beam Deflection techniques for concentration analysed in DCMIX 4 project, which refers to 0.0007 – 0.60 – 0.3993 and other fullerene concentrations around this value. Various thermophysical and optical properties which are necessary to determine thermodiffusion coefficients have been also measured.