Some aspects of a free jet phenomena to 105 L/D in a constant area duct

Under certain conditions, inlets with a Borda type geometry were shown to exhibit sufficiently strong separation effects to permit the working fluid to flow through the duct as if it were a free jet. Mass limiting flow data and associated pressure profiles for tubes of 14, 53, 64, 73, and 105 L/D with a Borda type inlet were taken to determine bounds of the free jet phenomena. For a given tube roughness, the limits appear to be one dimensional and dependent only on inlet stagnation conditions. For smooth tubes the upper L/D boundary is related by P sub R roughly equal to CT to the 17th power and sub R, C roughly equal to 00017 (L/D) to the 2.5 power where F sub R = P/P sub c is reduced pressure and T sub R = T/T sub c is reduced temperature. The lower bound appears to be saturation conditions at the inlet. Similar free jet effects were found for fluid hydrogen indicating that fluid jetting may be common to all fluids. While limited data on surface roughness show a decrease in the upper L/D limit, nevertheless fluid jetting still occurred

Metabolic simulation chamber

Metabolic simulation combustion chamber was developed as subsystem for breathing metabolic simulator. Entire system is used for evaluation of life support and resuscitation equipment. Metabolism subsystem simulates a human by consuming oxygen and producing carbon dioxide. Basic function is to simulate human metabolic range from rest to hard work

Two phase choke flow in tubes with very large L/D

Data were obtained for two phase and gaseous choked flow nitrogen in a long constant area duct of 16200 L/D with a diverging diffuser attached to the exit. Flow rate data were taken along five isotherms (reduced temperature of 0.81, 0.96, 1.06, 1.12, and 2.34) for reduced pressures to 3. The flow rate data were mapped in the usual manner using stagnation conditions at the inlet mixing chamber upstream of the entrance length. The results are predictable by a two phase homogeneous equilibrium choking flow model which includes wall friction. A simplified theory which in essence decouples the long tube region from the high acceleration choking region also appears to predict the data resonably well, but about 15 percent low

Finite element formulation for transient heat treat problems

The macrothermomechanical behavior of materials subjected to rapid thermal or mechanical loading such as occurs in most heat treatments is described. The equations are developed for Lagrangian, Eulerian, and intermediary kinematic descriptions and are independent of the constitutive laws and the equation of state; they can be solved numerically for a specified material and boundary conditions. The coupled transport effects between dissipation and energy are included. The conventional linearized stability approach indicates the numerical procedure to be stable, with certain restriction on the time step size

GASPLOT - A computer graphics program that draws a variety of thermophysical property charts

A FORTRAN V computer program, written for the UNIVAC 1100 series, is used to draw a variety of precision thermophysical property charts on the Calcomp plotter. In addition to the program (GASPLOT), which requires (15 160) sub 10 storages, a thermophysical properties routine needed to produce plots. The program is designed so that any two of the state variables, the derived variables, or the transport variables may be plotted as the ordinate - abscissa pair with as many as five parametric variables. The parameters may be temperature, pressure, density, enthalpy, and entropy. Each parameter may have as many a 49 values, and the range of the variables is limited only by the thermophysical properties routine

Two-phase choked flow of cryogenic fluids in converging-diverging nozzles

Data are presented for the two phase choked flow of three cryogenic fluids - nitrogen, methane, and hydrogen - in four converging-diverging nozzles. The data cover a range of inlet stagnation conditions, all single phase, from well below to well above the thermodynamic critical conditions. In almost all cases the nozzle throat conditions were two phase. The results indicate that the choked flow rates were not very sensitive to nozzle geometry. However, the axial pressure profiles, especially the throat pressure and the point of vaporization, were very sensitive to both nozzle geometry and operating conditions. A modified Henry-Fauske model correlated all the choked flow rate data to within + or - 10 percent. Neither the equilibrium model nor the Henry-Fauske model predicted throat pressures well over the whole range of data. Above the thermodynamic critical temperature the homogeneous equilibrium model was preferred for both flow rate and pressure ratio. The data of the three fluids could be normalized by the principle of corresponding states

Temperature and humidity control of simulated human breath

Subsystem was developed for breathing metabolic simulator which adjusts temperature and humidity of air to levels of human exhaled breath. Temperature-humidity subsystem is described, consisting of aluminum enclosure with 400 watt heat sheet glued to bottom, vertical separators, inlet connection, and check valve

Assessment of variations in thermal cycle life data of thermal barrier coated rods

An analysis of thermal cycle life data for 22 thermal barrier coated (TBC) specimens was conducted. The Zr02-8Y203/NiCrAlY plasma spray coated Rene 41 rods were tested in a Mach 0.3 Jet A/air burner flame. All specimens were subjected to the same coating and subsequent test procedures in an effort to control three parametric groups; material properties, geometry and heat flux. Statistically, the data sample space had a mean of 1330 cycles with a standard deviation of 520 cycles. The data were described by normal or log-normal distributions, but other models could also apply; the sample size must be increased to clearly delineate a statistical failure model. The statistical methods were also applied to adhesive/cohesive strength data for 20 TBC discs of the same composition, with similar results. The sample space had a mean of 9 MPa with a standard deviation of 4.2 MPa

Some flow phenomena in a constant area duct with a Borda type inlet including the critical region

Mass limiting flow characteristics for a 55 L/D tube with a Borda type inlet were assessed over large ranges of temperature and pressure, using fluid nitrogen. Under certain conditions, separation and pressure drop at the inlet was sufficiently strong to permit partial vaporization and the remaining fluid flowed through the tube as if it were a free jet. An empirical relation was determined which defines conditions under which this type of flow can occur. A flow coefficient is presented which enables estimations of flow rates over the experimental range. A flow rate stagnation pressure map for selected stagnation isotherms and pressure profiles document these flow phenomena

Metallic and metalloceramic coating by thermal decomposition

Metallic and metalloceramic coatings were prepared by thermal decomposition of a number of inorganic and metallo-organic compounds. The compounds were applied by spraying and by immersion, especially on ceramic fibers and fiber forms, which are easily coated by this procedure. Penetration of low-density ceramics is examined, and procedures are described that were used for converting the deposited materials to metals, oxides, or metal oxide films. Multiple-component films were also prepared. Photomicrographs illustrate the structure of these films