Analysis and design of optimized truncated scarfed nozzles subject to external flow effects

Rao's method for computing optimum thrust nozzles is modified to study the effects of external flow on the performance of a class of exhaust nozzles. Members of this class are termed scarfed nozzles. These are two-dimensional, nonsymmetric nozzles with a flat lower wall. The lower wall (the cowl) is truncated in order to save weight. Results from a parametric investigation are presented to show the effects of the external flowfield on performance

Experimental evaluation of two turning vane designs for fan drive corner of 0.1-scale model of NASA Lewis Research Center's proposed altitude wind tunnel

Two turning vane designs were experimentally evaluated for corner 2 of a 0.1 scale model of the NASA Lewis Research Center's proposed Altitude Wind Tunnel (AWT). Corner 2 contained a simulated shaft fairing for a fan drive system to be located downstream of the corner. The corner was tested with a bellmouth inlet followed by a 0.1 scale model of the crossleg diffuser designed to connect corners 1 and 2 of the AWT. Vane A was a controlled-diffusion airfoil shape; vane B was a circular-arc airfoil shape. The A vanes were tested in several arrangements which included the resetting of the vane angle by -5 degrees or the removal of the outer vane. The lowest total pressure loss for vane A configuration was obtained at the negative reset angle. The loss coefficient increased slightly with the Mach number, ranging from 0.165 to 0.175 with a loss coefficient of 0.170 at the inlet design Mach number of 0.24. Removal of the outer vane did not alter the loss. Vane B loss coefficients were essentially the same as those for the reset vane A configurations. The crossleg diffuser loss coefficient was 0.018 at the inlet design Mach number of 0.33

Detailed flow surveys of turning vanes designed for a 0.1-scale model of NASA Lewis Research Center's proposed altitude wind tunnel

Detailed flow surveys downstream of the corner turning vanes and downstream of the fan inlet guide vanes have been obtained in a 0.1-scale model of the NASA Lewis Research Center's proposed Altitude Wind Tunnel. Two turning vane designs were evaluated in both corners 1 and 2 (the corners between the test section and the drive fan). Vane A was a controlled-diffusion airfoil and vane B was a circular-arc airfoil. At given flows the turning vane wakes were surveyed to determine the vane pressure losses. For both corners the vane A turning vane configuration gave lower losses than the vane B configuration in the regions where the flow regime should be representative of two-dimensional flow. For both vane sets the vane loss coefficient increased rapidly near the walls

Experimental Evaluation of Turning Vane Designs for High-speed and Coupled Fan-drive Corners of 0.1-scale Model of NASA Lewis Research Center's Proposed Altitude Wind Tunnel

Two turning vane designs were experimentally evaluated for the fan-drive corner (corner 2) coupled to an upstream diffuser and the high-speed corner (corner 1) of the 0.1 scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. For corner 2 both a controlled-diffusion vane design (vane A4) and a circular-arc vane design (vane B) were studied. The corner 2 total pressure loss coefficient was about 0.12 with either vane design. This was about 25 percent less loss than when corner 2 was tested alone. Although the vane A4 design has the advantage of 20 percent fewer vanes than the vane B design, its vane shape is more complex. The effects of simulated inlet flow distortion on the overall losses for corner 1 or 2 were small

Supersonic investigation of two dimensional hypersonic exhaust nozzles

An experimental investigation was conducted in the NASA Lewis 10 x 10 ft supersonic Wind Tunnel to determine the performance characteristics of 2D hypersonic exhaust nozzles/afterbodies at low supersonic conditions. Generally, this type of application requires a single expansion ramp nozzle (SERN) that is highly integrated with the airframe of the hypersonic vehicle. At design conditions (hypersonic speeds), the nozzle generally exhibits acceptable performance. At off-design conditions (transonic to mid-supersonic speeds), nozzle performance of a fixed geometry configuration is generally poor. Various 2-D nozzle configurations were tested at off-design conditions from Mach 2.0 to 3.5. Performance data is presented at nozzle pressure ratios from 1 to 35. Jet exhaust was simulated with high-pressure air. To study performance of different geometries, nozzle configurations were varied by interchanging the following model parts: internal upstream contour, expansion ramp, sidewalls, and cowl

Comparison of analytical and experimental performance of a wind-tunnel diffuser section

Wind tunnel diffuser performance is evaluated by comparing experimental data with analytical results predicted by an one-dimensional integration procedure with skin friction coefficient, a two-dimensional interactive boundary layer procedure for analyzing conical diffusers, and a two-dimensional, integral, compressible laminar and turbulent boundary layer code. Pressure, temperature, and velocity data for a 3.25 deg equivalent cone half-angle diffuser (37.3 in., 94.742 cm outlet diameter) was obtained from the one-tenth scale Altitude Wind Tunnel modeling program at the NASA Lewis Research Center. The comparison is performed at Mach numbers of 0.162 (Re = 3.097x19(6)), 0.326 (Re = 6.2737x19(6)), and 0.363 (Re = 7.0129x10(6)). The Reynolds numbers are all based on an inlet diffuser diameter of 32.4 in., 82.296 cm, and reasonable quantitative agreement was obtained between the experimental data and computational codes

Experimental evaluation of corner turning vanes

Two types of turning vane airfoils (a controlled-diffusion shape and a circular arc shape) have been evaluated in the high-speed and fan-drive corners of a 0.1-scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. The high-speed corner was evaluated with and without a simulated engine exhaust removal scoop. The fan-drive corner was evaluated with and without the high-speed corner. Flow surveys of pressure and flow angle were taken for both the corners and the vanes to determine their respective losses. The two-dimensional vane losses were low; however, the overall corner losses were higher because three-dimensional flow was generated by the complex geometry resulting from the turning vanes intersecting the end wall. The three-dimensional effects were especially pronounced in the outer region of the circular corner

Selection of specific cell wall antigen for rapid detection of fish pathogenic Vibrio parahaemolyticus by enzyme immunoassay

An enzyme linked immunosorbant assay (ELISA) was developed, using polyclonal antibodies against a specific cell surface protein of Vibrio parahaemolyticus, for rapid detection of the organism. Nine virulent strains and one type strain of V. parahaemolyticus, one strain each of Vibrio vulnificus and Vibrio alginolyticus were used for the study. Cell surface proteins were extracted from all the strains and were analysed by SDS PAGE. One distinct band with molecular weight of 34 kDa, abundant in all the V. parahaemolyticus strains and lacks in other Vibrio species, was selected as cell wall antigen for immunisation. Polyclonal antibodies were raised against the selected 34 kDa protein of V. parahaemolyticus after preparative electrophoresis. An indirect plate ELISA was developed using this antiserum for detection of crude cell surface protein as well as whole cells of V. parahaemolyticus. All the 9 virulent strains and one type strain of V. parahaemolyticus tested, produced positive results, using the ELISA technique. To assess the specificity of the polyclonal serum, cross reaction studies with other Vibrio species such as V. vulnificus and V. alginolyticus were conducted by indirect plate ELISA. The results have clearly shown that antibodies directed against 34 kDa cell surface protein can be used for specific detection of fish pathogenic V. parahaemolyticus

Accessible Vehicle for Kids

The purpose of this document is to outline the process of developing a Go Baby Go vehicle for use by children with disabilities who experience limited or delayed mobility. The purpose of the project is to adapt the Wild Thing, a 12V commercially available ride-on toy car, so that young children with limited mobility can have similar opportunities to independently and actively explore their world for participation, play, learning, and engagement like their same-aged peers. The motivation for undertaking this project is to create a safe and universally designed form of active mobility for children who do not have access to a power wheelchair due to the lack of availability of appropriate products and funding sources for children with disabilities. The original design of the Wild Thing has two joysticks which can be moved by pushing the joysticks either both forward to go forward, both backwards to go backwards and one forward and one backwards in order to spin left or right. Because of this original design, children with limited mobility could have a difficult time navigating the Wild Thing platform. In order to meet this need, the vehicle will be redesigned to support varying options to control the vehicle. These include a single joystick, head array buttons, or hand-pushed buttons. Dependent on the child’s needs, these options can be chosen from, and implemented as the user sees fit. An app will also be utilized that allows control of the vehicle through the use of directional buttons and an emergency stop button. The app will also have the ability to log the usage data of the vehicle. This document contains the design aspects and process of this project