June 22, 2008
June 22, 2008
June 25, 2008
13.593.1 - 13.593.11
be made with minimum effort in the future. On the instrumentation front, pressure transducers and a data-logger were fully integrated with the wind tunnel measurement system. Variable inputs were geometric design parameters related to the truck cab and the collection bin sections, wind speed, and yaw angle (cab orientation). Output was dynamic pressure from fifty-four test points in the truck. Statistical analysis of normalized data using Minitab® included analysis of variance, linear regression analysis to establish significant input variables, and contour plots of the pressure fields generated in Excel®. The main effects account for half of the measured response, there are interactions between some main effects, and other probable variables exist. Brief descriptions of the changes to the wind tunnel, design and fabrication of the truck models, factorial design, and the experimental process are given below.
As mentioned above, the experimental study described in the present paper supported a M.S. Thesis work in the department. The investigation was comprehensive, rigorous and led to useful results and information that will be of immediate use to the industry at large. Additionally the tasks associated with the study such as the use of rapid prototyping equipment for making the test models will serve as the template for future such endeavors. Even though the redesigned tunnel was used to address the specific problem faced by the industry right now, the students gain valuable experience in solving practical problems of interest to present day industry as they work on a variety of applied projects using the tunnel.
Dry waste collection vehicles are faced with certain problems specific to the curbside collection process on residential streets. Specifically, this process involves the dumping of material from a container into the open section of the vehicle and moving to the next collection point. During the transit time, the truck cavity is open and the potential exists for the material to be forced to egress from the vehicle due to aerodynamic effects. The project described here was accepted based on industry request to study this issue and attempt to determine what critical elements are involved in exacerbating this condition.
To accomplish this, an experimental investigation was deemed to be the most logical approach. This required a wind tunnel of sufficient size and speed range as well as appropriately constructed models of the truck design being studied. Additionally, an experimental matrix with test parameters and appropriate output measures was necessary. The first step in this process was to establish key variables that could be studied and the measures indicating the response. With this task completed, it was important to assure that the tunnel was capable of achieving these conditions. The factors established for the study were wind speed, truck cab design (exterior configuration only), collection cavity design, and orientation of the front part of the truck to the wind. A two level fractional factorial design was established as a way to screen these variables in terms of their impacts as main effects to the response. The response chosen was the pressure distribution within the vehicle collection cavity (the open part of the bin). These factors could all be simulated in the tunnel through appropriate design of the tunnel and vehicle model, along with model modifications.
With the factors set and the levels of test established, the wind tunnel was reviewed relative to test capability. While important for the test at hand, this tunnel is also used extensively in the
Cuprak, R., & Rajadas, J., & Danielson, S. (2008, June), Experimental Study Of Waste Egress From Collection Vehicle Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. https://peer.asee.org/4335
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