摘要:

With introduction of the turbulent kinetic energy equation for the Reynolds stress term, the characteristics of compressible turbulent boundary layers along the wall of a rocket thrust chamber are theoretically solved. This inclusion of the turbulent kinetic energy equation provides the character of chemically reactive flow with mass injection and can exhibit the past history of boundary layers. Results show the variation of eddy viscosity in flow direction including the laminarization tendency in the nozzle convergent section. The results appears to be in good agreement with available experimental data. The eddy viscosity decreases significantly in the reactive hydrogen-oxygen boundary layer when a small amount of hydrogen is injected from the wall.

ISSN:0010-2202    

DOI:10.1080/00102207308952363

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102207308952364

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

A new analytical technique for the solution of nonlinear longitudinal combustion instability problems in rocket combustors is developed. Using relatively little computation time, this technique is capable of predicting the transient and limit cycle behavior of the combustion instability oscillations as well as the disturbance amplitude required to trigger an instability in a linearly stable motor. The limit cycle waveforms are found to exhibit shock wave characteristics for most unstable engine operating conditions. It is shown that the characteristics of the resulting instability are independent of the nature of the initial disturbance and they depend solely upon the engine operating conditions and the characteristics of the unsteady combustion process. Calculated results indicate that a second-order analysis can adequately describe the behavior of combustion instability oscillations over a broad range of engine operating conditions; however, higher order effects must be included in order to investigate engine triggering. A method for determining the combustion parametersnand τ from experimental data is proposed.

ISSN:0010-2202    

DOI:10.1080/00102207308952365

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

A mathematical model based on unreacted-core shrinking model is developed to describe the pyrolysis phenomena of the cellulosic materials in the temperature range of 700–1470°K. The relative importance of each model parameter is studied by applying the sensitivity analysis. The heat transfer control region and kinetic reaction control region are obtained from the developed model. The shift of controlling mechanism is dependent on the particle size and the wall temperature. The effect of heat of reaction on the temperature of the particle is also discussed.

ISSN:0010-2202    

DOI:10.1080/00102207308952366

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Experimental observations are made on the burning of a linear, uniformly spaced, single row of vertically oriented matchsticks, and on rows of continuous paperstrips, with an imposed wind, up to three feet per second, blowing with and opposed to the direction of fire spread. Matchstick height and spacing are varied. One height and row spacing are used for the paperstrips, and the number of rows is varied. Necessary conditions for flame propagation in the matchstick arrays are presented in a non-dimensional plot. Linear rates of flame propagation for the paper and matchstick arrays are presented as functions of the wind velocities for various spacings and heights. A correlation of the matchstick results is made by use of a semi-empirical model based on an ignition temperature and convective heat transfer. The experimental results are compared with previous work with no convection, of Emmons and Shen (1971) and Vogel and Williams (1970).

ISSN:0010-2202    

DOI:10.1080/00102207308952367

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102207308952368

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor