NISCAIR Online Periodicals Repository Collection: IJEMS Vol.11(1) [February 2004]
http://nopr.niscair.res.in/handle/123456789/8816
The Collection's search engineSearch the Channelsearch
http://nopr.niscair.res.in/simple-search
Analysis of reacting flows in an aero-engine afterburner using computational fluid dynamics
http://nopr.niscair.res.in/handle/123456789/30400
Title: Analysis of reacting flows in an aero-engine afterburner using computational fluid dynamics
<br/>
<br/>Authors: Unaune, Sunil V; Ganesan, V
<br/>
<br/>Abstract: <span style="mso-bidi-language:HI">In this paper, reacting flows in an aero-engine
afterburner are analyzed using computational fluid dynamics (CFD). A
computational procedure is described for calculating the three-dimensional
reacting flow fields in a gas turbine afterburner.
<span style="mso-bidi-language:HI">The computations are based on numerical solution
of time-averaged transport equations for mass, momentum, turbulent kinetic energy
and dissipation rate using a finite volume formulation. The numerical
calculations are performed using
<span style="mso-bidi-language:HI">SIMPLE(Semi Implicit Method for Pressure Linked
Equations). The RNG (Re-normalization Group Theory) k-ɛ model is used for
turbulence modeling. Combustion is modeled using PDF (Probability Density
Function). The results for air-fuel
<span style="mso-bidi-language:HI">Ratio of 30 and 46 are
obtained and analyzed.
</span></span></span></span>
<br/>
<br/>Page(s): 31-37Studies on 2,4,6-trinitrophloroglucinol (TNPG)—A novel flash sensitizer
http://nopr.niscair.res.in/handle/123456789/9264
Title: Studies on 2,4,6-trinitrophloroglucinol (TNPG)—A novel flash sensitizer
<br/>
<br/>Authors: Mehilal; Sikder, N; Sikder, A K; Survase, D V; Agrawal, J P
<br/>
<br/>Abstract: 2,4,6-Trinitrophloroglucinol
(TNPG), useful for percussion caps, detonator formulations and dye manufacture,
has been synthesized with conventional nitrating agents under mild reaction
conditions. The compound is characterized by IR, NMR, mass and elemental
analyses. Further, the purity of the compound is confirmed by estimation of
nitro groups. Thermal and explosive properties of TNPG have been investigated.
The detonation velocity and detonation pressure are also estimated.
<br/>
<br/>Page(s): 59-62Dielectric relaxation in glassy Se<sub>90</sub>Ge<sub>x</sub>In<sub>10-x</sub>
http://nopr.niscair.res.in/handle/123456789/9263
Title: Dielectric relaxation in glassy Se<sub>90</sub>Ge<sub>x</sub>In<sub>10-x</sub>
<br/>
<br/>Authors: Choudhary, N; Goel, D K; Kumar, A
<br/>
<br/>Abstract: Frequency and temperature dependence of dielectric constant (<b style=""><img src='/image/spc_char/italics_e.gif' border=0>'</b>) and dielectric loss (<b style=""><img src='/image/spc_char/italics_e.gif' border=0>''</b>)
are studied in glassy Se<sub>90</sub>Ge<sub>x</sub>In<sub>10-x</sub>, where x =
0, 2, 4, 6, 8 and 10, in the frequency range 1-10 kHz and in the temperature
range 293-400 K. The experimental results indicate that no dielectric
dispersion exist in glassy Se<sub>90</sub>Ge<sub>10</sub> alloy (x = 10).
However, when In concentration increases (x = 8, 6, 4, 2 and 0), dielectric
dispersion starts in the above frequency and temperature range. The values of <b style=""><img src='/image/spc_char/italics_e.gif' border=0>' </b>and <img src='/image/spc_char/italics_e.gif' border=0>'' at a particular temperature and frequency increase
with the increase in In concentration. An analysis of the observed dielectric
loss shows that the Guintini's theory of dielectric dispersion based on two
electron hopping over a potential barrier is applicable in the present case.
<br/>
<br/>Page(s): 55-58Compressive strength of lightweight aggregate concrete exposed to high temperatures
http://nopr.niscair.res.in/handle/123456789/9262
Title: Compressive strength of lightweight aggregate concrete exposed to high temperatures
<br/>
<br/>Authors: Bingöl, A Ferhat; Gül, Rüstem
<br/>
<br/>Abstract: In this paper, effects of high temperatures on the
compressive strength of concrete were investigated with the aim to produce a
fire resistant concrete. Thus, the mixture groups were determined by replacing
pumice for ordinary aggregate in the ratios of 25, 50, 75 and 100% in volume.
The temperature values were chosen as 150, 300, 450, 600 and 750°C.
The effects of heating duration over the compressive strength were also
examined, and the different types of concrete mixtures were heated for one
hour, three hours and five hours periods for each temperature values. It was
observed that concrete properties were deteriorated at 150°C and
the specimens began to lose some of their initial strengths at this
temperature. Though a considerable strength lose was not seen between 150-300°C,
all types of concrete mixtures continued to lose their compressive strength
after 300°C.
Every concrete mixture lost a significant part of their initial strength when
the temperature is reached up to 750°C. When the lightweight aggregate ratio is increased for
each temperature value, the loss of compressive strength of the concrete
compared to the initial strength was decreased. It was found that the heating
duration does not affect the strength loss significantly but a high temperature
is a more significant parameter on the strength loss.
<br/>
<br/>Page(s): 68-72