• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.10 s.241
• /
• pp.1075-1082
• /
• 2005

The characteristics of longitudinal dispersion enhancement by the flow oscillation are numerically studied according to various groove geometries in a 2-D channel in the present study. The length of expanded section l$_{1}$/h$_{1}$ is varied from 0 to 8.75. The oscillating flow condition is given at both side ends, i.e., u = Asin ($2{\pi}ft$) The non-dimensional temperatures at both side ends are set to zero. The bottom and top walls are adiabatic. The local heat sources are located at the middle of the groove wall. In order to solve the governing equations, the SIMPIER algorithm is employed. The present results indicate that maximum longitudinal thermal dispersion can be achieved when the area ratio of the expanded section to the contracted section in the grooved channel becomes 1.

• 한국연소학회:학술대회논문집
• /
• 2003.05a
• /
• pp.111-117
• /
• 2003

The present study discusses about the combustion and thermal flow characteristics of a G+R type incinerator, which is under construction for MAPO Incineration system, to evaluate the effects of various operating and design parameters. A bed combustion model is developed to simulate the waste bed combustion on the stoker. The effects of waste composition and primary air distribution are estimated. The results of the waste bed combustion model is applied to CFD(computational fluid dynamics) simulation, which simulates the detail of the thermal flow in the combustion chamber. The effects of bypass damper opening ratio, primary air distribution, and secondary air jet configuration are discussed.

• Journal of Environmental Science International
• /
• v.11 no.6
• /
• pp.543-551
• /
• 2002

A Numerical simulation on the thermal flow performance was carried out to propose the incinerator type for the domestic refuses and to investigate the design factor and operating conditions. The SSTI(Standard Stoker Type Incinerator) proposed in this study was modified from the type with central f)ow. It has the characteristics of good mixing between refuse and hot combustion gas in primary combustion chamber and between unburned gas inflowing and secondary air jet in secondary chamber. By predictive results, the SSTI was no recirculation zone in secondary chamber so that mixing time was increased with high residence time. It has good characteristics of combustion and low emission. Parametric screening studies have been understood with phenomenon of combustion in incinerator.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.11
• /
• pp.3046-3056
• /
• 1994

To design and develop a turbocharged engine, it needs that many studies must be preceded about the characteristics of engine performance and thermal flow. To accomplish this purpose, turbocharger was equipped to 1.3 liter naturally aspirated gasoline engine. The temperature probe of plate type was designed and it was installed into the combustion chamber wall to measure unsteady temperature. The unsteady heat flux at combustion chamber wall was evaluated using one dimensional unsteady conduction equation with the wall temperature and temperature gradient.

• 한국연소학회:학술대회논문집
• /
• 2000.05a
• /
• pp.35-44
• /
• 2000

It was numerically studied that NOx emission characteristics of confined $CH_{4}$ jet flames with the variation of the diameter of inner fuel nozzle, the flow rate of $CH_{4}$ and equivalence ratio. Parabolic type equations were adopted in the calculation and GRI-2.1I mechanism was used for the chemical reaction. NOx emission index (EINOx) was introduced to evaluate NOx emission quantitatively in parametrically varied flames and the contribution of Thermal and Prompt NO mechanism was discussed. The results showed that Total EINOx varied sensitively with the variation of the flow rate of$CH_{4}$ but it was not sensitive to the variation of the diameter of inner fuel nozzle. Thermal EINOx showed the similar tendency to total EINOx and Prompt EINOx showed insensitivity to the variation of the diameter of inner fuel nozzle and the flow rate of $CH_{4}$.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.130-135
• /
• 2000

To enhance heat transfer characteristics of water, fine ice was added to it. The convective heat transfer characteristics of the ice slurry were investigated in a flow loop with a constant heat flux test section. The Nusselt number and Fanning friction coefficient of water flow were found to be similar to the expected curve by Petukhov. The Nusselt number of the ice sin flow was higher than the Nusselt number of water. Effective thermal capacity of the 10.84% ice slurry was found to have 2.39 times of the thermal capacity of water.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.6
• /
• pp.503-511
• /
• 2002

Heat flow characteristics during hot water extraction process was studied experimentally. Data were taken at various outlet port type for the fixed inlet port type, inlet-outlet temperature differences and mass flow rates. In this study, the temperature distribution in a storage tank and an outlet temperature were measured to predict a degree of stratification in the storage tank, and a useful rate of hot water was analysed with respect to the variables dominating a extraction process. Experimental results show that the degree of stratification and useful rate of hot water are all high in a low flow rate in case of using modified distributor I (MDI) as the outlet port type.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2297-2302
• /
• 2007

Numerical simulations are conducted to analyze conjugate heat transfer characteristics in a ribbed channel. In this simulation, the effects of Reynolds number and heat capacity of the solid channel wall on convective heat transfer are observed in the turbulent flow regime. In the case of the conducting wall against isothermal wall, the relative ratio of the thermal resistance between the solid wall and the flow field varies with Reynolds number. Thus the characteristics of the conjugate heat transfer are changed with the Reynolds number. Heat capacity ratio affects the temperature fluctuation inside solid wall. The temperature fluctuation inside the solid wall decreases with increasing the heat capacity of the solid wall so that the convective heat transfer increases. When the thermal conductivity ratio is smaller than 10, the effects of flow characteristics on heat transfer are changed.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.11a
• /
• pp.403-408
• /
• 1996

The subchannel analysis was performed to verify the behavior of hot channel characteristics and obtain the information to support the core thermal-hydraulic behavior at post-trip steam line break with low flow condition. During this postulated accident, buoyancy-induced cross flow occurs, and the coupled nuclear and thermal-hydraulic interactions become important. The code predictions with TORC are in good agreement with the test data. Under such conditions, the mass flow increase in the hot channel by buoyancy-induced cross flow depends on the parameter $GR^{*}\;/\;Re^2$, and buoyancy effect becomes more noticeable as $GR^{*}\;/\;Re^2$ increases.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1736-1741
• /
• 2003

The characteristics plasma flow of an atmospheric plasma torch used for thermal plasma processing is studied. In general, it is produced by the arc-gas interactions between a cathode tip and an anode nozzle. The performance of non-transferred plasma torch is significantly dependent on jet flow characteristics out of the nozzle. In this work, the distribution of gas flow that goes out to the atmosphere through a plenum chamber and nozzle is analyzed to evaluate the performance of atmospheric plasma torch. Numerical analysis is carried out with various angles of an inlet flow which can create different swirl flow fields. Moreover, the size of plasma plume is experimentally depicted.