• Journal of the Korean Applied Science and Technology
• /
• v.8 no.2
• /
• pp.145-151
• /
• 1991

Hazadous properties were evaluated for Alkyl nitrates such as hexyl nitrate, decyl nitrate, dodecyl nitrate and 2-methyl pentyl nitrate, 2-hexyl ethyl nitrate. The thermochemical properties such as heat of vaporization, boiling point, flash point and kinetic parameter for aliphatic nitrate were measured to determine the hazadous properties of these compounds. The boiling points and heat of vaporization increase as the increase of alkyl chain length in alkyl nitrates. Flash point is a linear function of boiling point as same as alkanes. The rate equation in isothermal decomposition are 1/2 order and compensation effect is found between logarithm of frequency factor the activation energy, then the decomposition preceeds with simlar reaction mechanism for each nitrate.

• Journal of ILASS-Korea
• /
• v.28 no.2
• /
• pp.89-96
• /
• 2023

This study presents a numerical simulation investigating hydrodynamic characteristics of high-temperature hydrocarbon aviation fuel injected through a plain orifice injector. The analysis encompassed the temperature range up to the critical point, and the obtained results were compared with prior experimental observations. The analysis unveiled that the injector's exit pressure remains equivalent to the ambient pressure when the fuel injection temperature is below the boiling point. However, when the fuel temperature surpasses the boiling point, the exit pressure of the injector transitions to the saturated vapor pressure corresponding to the fuel injection temperature. Consequently, the exit pressure of the injector increases in tandem with the rapid increase of the saturation vapor pressure due to escalating fuel temperatures. This rise in the exit pressure necessitates a proportional increase in fuel injection pressure to ensure a fixed fuel mass flow rate. Furthermore, the investigation revealed that the discharge coefficient obtained by applying the exit pressure instead of the ambient pressure did exhibit no decrease, but rather was maintained at a nearly constant value, comparable to its level below the boiling point.

• Nuclear Engineering and Technology
• /
• v.35 no.4
• /
• pp.274-285
• /
• 2003

Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Loop for Transient Analysis). Two test sections are made of copper to maintain Bi below 0.1. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of both the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the two test sections. The measured heat transfer coefficients for the test section with diameter 120 mm lie within the bounding values from the laminar film boiling analysis, while those for diameter 294 mm are found to be greater than the numerical results on account of the Helmholtz instability. There is little difference observed between the film boiling heat transfer coefficients measured from the two test sections. In addition, the higher thermal conductivity of copper results in the higher minimum heat flux in the tests. For the test section of diameter 120 mm, the Leidenfrost point is lower than that for the test section of diameter 294 mm. Destabilization of film boiling propagates radially inward for the 294 mm test section versus radially outward for the 120 mm Test Section.

• Journal of the Korean Society of Safety
• /
• v.13 no.4
• /
• pp.192-198
• /
• 1998

MRSM(modified response surface methodology)-2 model is presented for the prediction of boiling points in combustible solution of quaternary systems. This model requires only normal boiling points of pure substances and group-group parameters which are based on the group-group concepts without the use of experimental data under consideration. By means of this methodology, it is possible to predict the boiling points of the combustible mixture of quaternary systems by plotting of isothermal lines using computer graphics. The proposed methodology has been tested and compared successfully with reported boiling points in journals for the combustible solution of quaternary systems. It is hoped eventually that this methodology will permit prediction of the flash point and flammability limit for the combustible mixture of multicomponent systems.

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.5
• /
• pp.707-716
• /
• 2008

The objective of this study was to analyze the effect of mixed fuel composition and mass fraction on spray inner structure in evaporating transient spray under the variant ambient conditions. Spray structure and spatial distribution of liquid phase concentration were investigated using a thin laser sheet illumination technique on the three component mixed fuels. A pulsed Nd:YAG laser was used as a light source. The experiments were conducted in a constant volume vessel with optical access. Fuel was injected into the vessel with electronically controlled common rail injector. Used fuel contains i-octane($C_8H_{18}$), n-dodecane($C_{12}H_{26}$) and n-hexadecane($C_{16}H_{34}$) that were selected as low-, middle- and high-boiling point fuel, respectively. Experimental conditions are 42 MPa, 72 MPa and 112 MPa in injection pressure, $5\;kg/m^3$, $15kg/m^3$ and $30kg/m^3$ in ambient gas density, 300 K, 500 K, 600 K and 700 K in ambient gas temperature, 300 K and 368 K in fuel temperature and different fuel mass fraction. Experimental results indicated that the multi-component fuels made two phase region mixed vapor and liquid so that it would are helpful to improve combustion, for the fuels of high boiling point component could accelerate evaporation very much according as low boiling point fuel was added to high boiling point fuel.

• Journal of Sensor Science and Technology
• /
• v.22 no.6
• /
• pp.404-409
• /
• 2013

We devised calibration procedure for industrial thermometers by a comparison method at the boiling point of nitrogen (${\sim}-196^{\circ}C$). The uncertainty of the calibration was 4 mK (k = 2). As experimentally demonstrated in this work, the effect of the atmospheric pressure on the boiling point of nitrogen can be easily detected by the thermometer. Therefore, when the boiling point of nitrogen is used for calibration of thermometer by comparison, either a reference thermometer must be used to provide the reference temperature or the effect of atmospheric pressure should be carefully considered. The use of a copper block with a large thermal mass soaked into the liquid nitrogen was proven to be more reliable, and the stability of the temperature immersed into the copper block was 1.4 mK. The temperatures at the thermometer wells, evaluated by the crossed-measurement method to compensate for the inaccuracy of the thermometers and the linear drift of the temperature of the copper block, were equivalent within 0.23 mK of standard uncertainty.

• Journal of The Korean Association For Science Education
• /
• v.26 no.7
• /
• pp.805-812
• /
• 2006

In this study the description patterns of chemistry textbooks on the boiling point elevation phenomenon and the understanding patterns of high school students, pre-service teachers and chemistry teachers were investigated. High school chemistry II textbooks developed in the 6th and 7th national curricula were analyzed and the conception patterns of subjects on this phenomenon were categorized using a questionnaire developed for this study. The description patterns of science textbooks were classified into three: 'decreasing of surface solvent molecules', 'attraction force between solvent and solute molecules' and 'decreasing of surface solvent molecules and attraction force between solvent and solute molecules'. In the result of the conception analysis, the ratio of 'attraction force between solvent and solute molecules' was high among students, pre-service teachers, and chemistry teachers. There was a propensity that they would like to explain the boiling point elevation in terms of enthalpy rather than entropy, and in order to analyze this propensity, follow-up interviews were carried out.

• Journal of Environmental Health Sciences
• /
• v.32 no.4 s.91
• /
• pp.262-267
• /
• 2006

DBPs and T&O(taste-and-odor) compounds in drinking water is one of main source to deteriorate water quality. So, these compounds can cause adverse health effects and result in many consumer complaints aesthetically. This experiments carried out to investigate the effect of boiling water on DBPs and T&O compounds in the tap water. THMs and TCM concentration were reduced by 91.3%, 88.9% after 5 min of boiling, respectively. It is certainly, resulted from volatilization of TCM. TCAA concentration decreased when the water was boiled, too. By contrast, the concentration of DCAA was increased with duration time from boiling-point. The reduction of TCAA from the boiled water can be attributed to chemical transformation like decarboxylation. T&O compounds such as geosmin and 2-MIB was effectively removed by boiling of water, resulting in the removal efficiency of 97.1%, 94.4% after 5 min of boiling, respectively.

• Clean Technology
• /
• v.19 no.3
• /
• pp.233-242
• /
• 2013

The influences of Ca and Fe based oxides as dechlorination sorbents on the product distribution, boiling point distribution of liquid product, concentration of Cl of the products from the pyrolysis of PVC containing combustible wastes were investigated. With Fe based oxides as the sorbents, the yield of liquid product remarkably decreased whereas the decrease of the boiling point distribution of the liquid product was not noticeable. This phenomenon indicated that Fe based oxides worked as catalysts with weak catalytic activity. With Ca based oxides as the sorbents, the yield of liquid product did not decrease and the boiling point distribution of liquid product did not change significantly, but the dechlorination performance of these was much better than that with Fe based oxides.

• Korean Journal of Food Science and Technology
• /
• v.23 no.5
• /
• pp.605-609
• /
• 1991

The physical properties which must be considered as engineering factors affecting on the evaporation process of fruit juices are boiling point rise, density, viscosity, thermal conductivity and specific heat. These factors are varied with food ingredients, soluble solids, pressure and temperature. In the reserch, it has been worked to obtain the data and to develop prediction model for the boiling point rise as a faction of soluble solid and pressure by the regression of SPSS package program. For the prediction model of density, it was developed as a fuction of soluble solid content on apple and pear juices. For the viscosity model, it was establised by the factors of temperature and content of soluble solid through the optimization program.