Heat transfer characteristics of jet impingement onto the concave surface of a cone

• Published in: Experimental heat transfer 2024-04, Vol.37 (3), p.246-270
• Main Authors: Gorasiya, A V, Vedula, R P
• Format: Article
• Language: English
• Subjects: Aerodynamics; Aircraft; Aircraft icing; Apex angle; concentric and offset jet impingement; conical surface; Diameters; Flat plates; Flat surfaces; Fluid flow; Gas turbine engines; Gas turbines; Heat flux; Heat transfer; Heat transfer coefficients; Ice formation; Infrared cameras; Jet impingement; Metal foils; Nusselt number; pressure coefficient; Reynolds number; Stagnation point; Stainless steels; Static pressure; Surface temperature
• ISSN: 0891-6152; 1521-0480
• DOI: 10.1080/08916152.2022.2126029

Heat transfer coefficient measurements for jet impingement onto the concave surface of a cone with apex angles equal to 30° and 70° are reported in this study. Static pressure measurements along the cone surface are also reported which aid in explaining the results from the heat transfer measurements. The conical geometry finds application for the heating of aircraft gas turbine engine nose bullet region which could experience ice formation whenever aircraft operates at higher altitudes. The concave surface of the cone is heated by impinging hot air tapped from the compressor. The heat transfer coefficients, which are significantly different compared to flat surface impingement, and are scarcely available, are reported in this study. The influence of the jet axis coincident with the cone axis and impinging into apex region was studied first. The methodology where a thin stainless-steel foil is heated with a known heat flux by passing electric current through it and then measuring the detailed surface temperature using an infrared thermal camera, was used to compute the wall Nusselt distribution. The Nusselt number variation is presented as a function of nondimensional apex to nozzle spacing (L/D) and the nondimensional axis displacement (O/D). Three different diameter (D equal to 10 mm,14 mm and 20 mm) pipes were used for the concentric impingement case and the Nusselt number distribution was observed not depend on the injection diameter. The jet Reynolds number was varied between 25000 and 82000. The peak Nusselt number values are similar to those for flat plate impingement and do not occur at the cone apex, but at a nondimensional distance between 3.2 and 3.9 for 4.25