Measurement of confined heated circular jet

• Main Author: Tan, George Chun Boon.
• Other Authors: Chua Leok Poh
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering::Fluid mechanics
• Online Access: http://hdl.handle.net/10356/40601
• Institution: Nanyang Technological University

The experiment of a confined heated circular jet was conducted to simulate the actual flow field of fire in an enclosed compartment. Velocity measurements of the flow were obtained for the study in the experiment, using wire anemometry technique as the data acquisition method. The experiment was conducted in two phases, whereby the first phase used a single-wire probe, followed by a cross-wire probe used in the second phase to measure the required data in each phase. The experimental mean velocity profile observed was found to have reached self-preservation almost immediately after the potential core region, which was deduced to be at x/d = 3. The experimental mean velocity profile was deduced to be similar to that of the flow characteristic of fire in terms of resembling its Gaussian shape profile, which indicated that the project would reflect a fairly accurate simulation of fire in an enclosed compartment. The Reynolds normal and shear stress profiles, in contrast to the mean velocity profile, had not reached self-preservation, which indicated that the turbulent zone in the project was not fully developed. This was deduced to be due to insufficient development length used in the project. The jet decay rate for the centerline mean velocity was deduced to be higher in the project, as compared to the decay rates found in other researchers‟ circular jet experiments. This was due to the smaller Reynolds number for the flow used in the project. On the other hand, the jet spread rate was found to have an inverse relationship with the decay rate and this holds true for the experiments of the same group of researchers.