mesh to the fine mesh uses bilinear inter- model and program were developed for (2) simulation functions that predict the polation; and prolongation of the coarse use in designing and predicting the response of the mixer to variations in the grid solution uses bicubic interpolation. performances of turbopumps for cryo- properties of the LH2 and GH2 and man- This program was written by Raymond E. genic fluids. Prior numerical models ual- or feedback-control variations in Mineck, James L. Thomas, and Robert T. used for this purpose do not account valve positions. The GUI enables schedul- Biedron of Langley Research Center and for either the variability of properties of ing of a sequence of operations that in- Boris Diskin of the National Institute of cryogenic fluids or the thermal effects cludes switching from manual to feed- Aerospace. Further information is contained (especially, evaporative cooling) in- back control when a certain event occurs. in a TSP (see page 1). volved in cavitation. It is important to This program was written by Fernando LAR-16608-1 account for both because in a cryogenic Figueroa of Stennis Space Center, Hanz fluid, the thermal effects of cavitation Richter of the National Research Council, are substantial, and the cavitation char- and Enrique Barbieri and Jamie Granger acteristics are altered by coupling be- Austin of Tulane University. Doclet To Synthesize UML tween the variable fluid properties and Inquiries concerning rights for the commer- The RoseDoclet computer program the phase changes involved in cavita- cial use of this invention should be addressed extends the capability of doclet soft- tion. The present model accounts for to the Intellectual Property Manager, Stennis ware to automatically synthesize Unified both thermal effects and variability of Space Center, (228) 688-1929. Refer to SSC- Modeling Language (UML) content properties by incorporating a general- 00213. from Java language source code. [Do- ized representation of the properties of clets are Java-language programs that cryogenic fluids into a generalized com- use the doclet application programming pressible-fluid formulation for a cavitat- interface (API) to specify the content ing pump. The model has been exten- Control Program for an and format of the output of . sively validated for liquid nitrogen and Optical-Calibration Robot Javadoc is a program, originally de- liquid hydrogen. Using the available A computer program provides semiau- signed to generate API documentation data on the properties of these fluids, tomatic control of a moveable robot used from Java source code, now also useful the model has been shown to predict to perform optical calibration of video- as an extensible engine for processing accurate temperature-depression val- camera-based optoelectronic sensor sys- Java source code.] RoseDoclet takes ad- ues. tems that will be used to guide auto- vantage of Javadoc comments and tags This program was written by Ashvin mated rendezvous maneuvers of already in the source code to produce a Hosangadi, Vineet Ahuja, and Sanford M. spacecraft. The function of the robot is UML model of that code. RoseDoclet Dash of Combustion Research and Flow Tech- to move a target and hold it at specified applies the doclet API to create a doclet nology, Inc., for Marshall Space Flight Cen- positions. With the help of limit switches, passed to Javadoc. The Javadoc engine ter. For further information, contact Ashvin the software first centers or finds the tar- applies the doclet to the source code, Hosangadi at [email protected]. get. Then the target is moved to a start- emitting the output format specified by MFS-32140 ing position. Thereafter, with the help of the doclet. RoseDoclet emits a Rose an intuitive graphical user interface, an model file and populates it with fully operator types in coordinates of speci- documented packages, classes, methods, fied positions, and the software responds variables, and class diagrams identified GUI for Computational by commanding the robot to move the in the source code. The way in which Simulation of a Propellant target to the positions. The software has UML models are generated can be con- Mixer capabilities for correcting errors and for trolled by use of new Javadoc comment Control Panel is a computer program recording data from the guidance-sensor tags that RoseDoclet provides. The ad- that generates a graphical user interface system being calibrated. The software vantage of using RoseDoclet is that (GUI) for computational simulation of a can also command that the target be Javadoc documentation becomes lever- rocket-test-stand propellant mixer in moved in a predetermined sequence of aged for two purposes: documenting the which gaseous hydrogen (GH2) is in- motions between specified positions and as-built API and keeping the design doc- jected into flowing liquid hydrogen can be run in an advanced control mode umentation up to date. (LH2) to obtain a combined flow having in which, among other things, the target This program was written by Matthew R. desired thermodynamic properties. The can be moved beyond the limits set by Barry and Richard N. Osborne of United GUI is used in conjunction with software the limit switches. Space Alliance for Johnson Space Center. that models the mixer as a system having This program was written by Albert (Nick) For further information, contact the Johnson three inputs (the positions of the GH2 Johnston of Marshall Space Flight Center. Technology Transfer Office at (281) 483- and LH2 inlet valves and an outlet valve) For further information, contact Sammy 3809. and three outputs (the pressure inside Nabors, MSFC Commercialization Assistance MSC-23580 the mixer and the outlet flow tempera- Lead, at [email protected]. MFS- ture and flow rate). The user can specify 31925-1 valve characteristics and thermodynamic properties of the input fluids via user- Computing Thermal Effects friendly dialog boxes. The user can enter of Cavitation temporally varying input values or tempo- SQL-RAMS in Cryogenic Liquids rally varying desired output values. The SQL-RAMS (where “SQL” signifies A computer program implements a GUI provides (1) a set-point calculator Structured Query Language and numerical model of thermal effects of function for determining fixed valve posi- “RAMS” signifies Rocketdyne Auto- cavitation in cryogenic fluids. The tions that yield desired output values and mated Management System) is a succes-

14 NASA Tech Briefs, November 2005