Temperature Measurement of Fluid Flows by Using a Focusing Schlieren Method

Abstract

A method for measuring planar temperature fields of fluid flows is proposed. The focusing schlieren technique together with a calibration procedure to fulfill such a purpose is used. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens. The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the hot air. The experimental values of temperature measurements are in agree with those measured using a thermocouple.

Supersonic cylinder wake dynamics

“…2020; Martinez-Gonzalez et al. 2018), so here only the set-up, performance and the capability of the present system are described.…”

A non-axisymmetric temperature field reconstruction method based on the interferometric fringe schlieren method

“…In 2017, Min et al [18] used this method to image air turbulence caused by candles, boiling kettles, heaters and gas torches under laboratory conditions. In 2018, Martínez-González et al [19] used this method to devise a method to measure the fluid plane temperature field and the hot air plane temperature field emitted by the nozzle of a commercial hot air gun during welding. However, such methods require the construction of complex optical path systems with an observational area limited by the size of the optical lens, generally only adaptable to a laboratory environment.…”