Browsing by Author "Zhang, Mingyang"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Corrosion Studies of Molten Chloride Salt: Electrochemical Measurements and Forced Flow Loop Tests
    Zhang, Mingyang (Virginia Tech, 2023-08-23)
    This study encompasses various aspects of corrosion in chloride molten salt environments, employing electrochemical techniques and a forced convection loop. It explores corrosion thermodynamic properties, electrochemical corrosion kinetics, and flow-induced dynamic corrosion. The study developed a novel electrochemical method for measuring thermodynamic properties of corrosion products and develops a new analysis theory for potentiodynamic polarization data obtained from cathodic diffusion-controlled reactions. Additionally, the design and operation experience of a forced convection chloride molten salt loop is shared. Particularly, the study presents novel findings on the turbulent flow-induced corrosion phenomenon and mechanism of Fe-based alloys in Mg-based chloride molten salt. These outcomes provide valuable insights into the corrosion mechanisms and flow-induced corrosion of Fe-based alloys in chloride molten salt. The results and experiences shared in this paper have implications for the successful implementation of molten salt as an advanced heat transfer fluid and thermal energy storage material in high-temperature applications, benefiting the nuclear and concentrating solar communities.
  • Thumbnail Image
    Detailed Heat Transfer Measurements of Various Rib Turbulator Shapes at Very High Reynolds Numbers Using Steady-state Liquid Crystal Thermography
    Zhang, Mingyang (Virginia Tech, 2018-01-18)
    In order to protect gas turbine blades from hot gases exiting the combustor, several intricate external and internal cooling concepts are employed. High pressure stage gas turbine blades feature serpentine passages where rib turbulators are installed to enhance heat transfer between the relatively colder air bled off from the compressor and the hot internal walls. Most of the prior studies have been restricted to Reynolds number of 90000 and several studies have been carried out to determine geometrically optimized parameters for achieving high levels of heat transfer in this range of Reynolds number. However, for land-based power generation gas turbines, the Reynolds numbers are significantly high and vary between 105 and 106. Present study is targeted towards these high Reynolds numbers where traditional rib turbulator shapes and prescribed optimum geometrical parameters have been investigated experimentally. A steady-state liquid crystal thermography technique is employed for measurement of detailed heat transfer coefficient. Five different rib configurations, viz., 45 deg., V-shaped, inverse V-shaped, W-shaped and M-shaped have been investigated for Reynolds numbers ranging from 150,000 to 400,000. The ribs were installed on two opposite walls of a straight duct with aspect ratio of unity. For very high Reynolds numbers, the heat transfer enhancement levels for different rib shapes varied between 1.3 and 1.7 and the thermal hydraulic performance was found to be less than unity.