Search Results

Too often many heat management problems are not solved with thermal analysis because of excessive complexity, time, and cost. A method for quickly solving a sophisticated thermal/fluid system with minimal user interaction and with common desktop computer resources is presented. A desktop (Microsoft Windows™) thermal analysis package, WinTherm, consists of the Generic Processor (pre-processing software), the 3-D Thermal Model (a finite difference nodal network solver), and an Image Viewer (wireframe and animated thermal display). The theoretical basis for this thermal analysis toolkit will be discussed as well as examples of its implementation.

Up to 80 percent of the total hydrocarbons emitted during the EPA Federal emissions test are produced in the first five minutes of this procedure. It has been theorized that this is in part due to wall wetting of the intake port and cylinder. This study measures the behavior of the fuel film thickness in the intake port during cold starting, steady state and transient operation. Three injector spray patterns with varying droplet sizes were utilized for the tests. The fuel film thickness in the intake port of a Ford 1.9L engine was measured using optical sensors. It was found that the spray pattern and droplet size affected the port wall wetting characteristics.

A simple geometry pneumatic atomizer which could be used on internal combustion engine was tested with water as the working fluid. The pneumatic atomizer consists of a cylindrical chamber with an orifice plate at the outlet end. Liquid flows down the chamber walls and onto the nozzle orifice plate as a film. Air flows down the center of the chamber. The interaction of the air and water, which occurs at the orifice, atomizes the water. Large droplets form near the nozzle orifice and break up as they go down stream. Variations in the droplet size occurred in the spray. When geometry and flow rates were varied, changes which decreased the water film thickness or increased the air velocity at the nozzle orifice yielded smaller droplets in the spray. Droplet size data was measured by Malvern Laser Particle Sizer.