The influence of uniform flow orifice on the effect of Naturally stratified Chilled water-storage tank
The widely use of cooled storage technology in our country will be an irreversible trend with the development and improvement of the TOU price policy. Naturally stratified Chilled water-storage is a very important cool storage technology. In this paper, the effect of using uniform flow orifice in naturally stratified water-storage with slotted pipe diffuser is studied by contrast experiments firstly. Then the cases with uniform flow orifice are simulated. Through the comparison of experimental data and simulation data, the correctness of the mathematical model is verified. Finally, the effect of water-storage is studied by simulation when the uniform flow orifice is set with different voltage drop. Conclusions can be obtained as follows: the layered effect is greatly improved by setting the uniform flow orifice; it is when the voltage drop of uniform flow orifice is in an appropriate range which is about ten to tens Pa that the improvement is obvious.
The effect of diffuser configuration on thermal stratification in a rectangular storage tank
This study is to systematically analyze the effect of various kinds of design factors on the stratification performance of a rectangular storage tank. Special interest is focused on the diffuser configuration, which crucially impacts the performance of a storage tank. Herein, a new diffuser shape is proposed, which exemplifies improved performance. Three-dimensional unsteady numerical experiments are conducted for four design parameters of a stratified thermal storage tank: Three design parameters with three levels (i.e., the Reynolds number=400, 800, and 1200; the Froude number=0.5, 1.0, and 2.0; and the area ratio of the diffuser to tank cross-section=0.0327, 0.0582, and 0.131) and one design parameter having two levels (i.e., diffuser type=radial plate type and radial adjusted plate type). Orthogonal array L18(2×37) is adopted for the analysis of variance. The result gives quantitative estimation of the various design parameters affecting the performance and helps to determine the main factors for the optimum design of a stratified thermal storage tank. In the range of parameters considered, the Reynolds number is found to be the most dominant parameter. Moreover, the diffuser shape plays a significant role on the performance of a stratified thermal storage tank.
HYPERGOLIC REACTION MECHANISMS OF CATALYTICALLY PROMOTED FUELS WITH ROCKET GRADE HYDROGEN PEROXIDE
Abstract The coupling of the physical and chemical processes controlling the ignition delays (τ ign ) of hypergolic propellants complicates the direct analysis of the transient ignition processes. The transport properties of both the propellants and the ambient gas, and the heat of vaporization and reaction affect τ ign and must be considered experimentally. Furthermore, since hypergolic ignition occurs, by definition, on contact, the mechanics of initial contact and subsequent mixing can affect τ ign and must also be considered. Experimental results from a study of the hypergolic ignition of a catalytically promoted fuel with rocket grade hydrogen peroxide (RGHP) are presented. Statistical analysis of the experimental data was conducted to evaluate the relative effects of RGHP concentration, initial ambient pressure, and the ambient gas on τ ign . At RGHP concentrations of less than 92% in water, stable ignition was difficult to achieve. At sufficiently high Lewis number, an oscillatory ignition process is observed. A phenomenological model comprising mixing, RGHP decomposition, fuel heating and vaporization, and auto-ignition is presented and compared to the experimental results.