• Particle and aerosol research
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• v.12 no.1
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• pp.21-26
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• 2016

In order to realize In-line and convenient measurement for solid-gas two phase flows, Light Transmission Fluctuation (LTF) based on the random variation of transmitted light intensity, light scattering theory and cross-correlation method was presented for online measurement of particle size, concentration and velocity. The statistical relationship among transmitted light intensity, particle size and particle number in measurement zone was described by Beer-Lambert Law. Accordingly, the particle size and concentration were determined from the fluctuation signal of transmitted light intensity. Simultaneously, the particle velocity was calculated by cross-correlation analysis of two neighboring light beams. By considering the influence of concentration variation in industrial applications, the improved algorithm based on spectral analysis of transmitted light intensity was proposed to improve measurement accuracy and stability. Therefore, the online measurement system based on LTF was developed and applied to measure pulverized coal in power station and raw material in cement plant. The particle size, concentration and velocity of powder were monitored in real-time. It can provide important references for optimal control, energy saving and emission reduction of energy-intensive industries.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.109-113
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• 1999

Thermal mass flow meter (TMF) is used measuring the small mass flow rate of gases. Generally, flow rate measuring accuracy of TMF is $\pm2{\%}$ of full scale. TMF is manufactured for specified working pressure and specified working gas by customer. If it were applied for different working pressure and gases, flow rate measurement accuracy decreased dramatically. In this study, a TMF tested with three different gases and pressure range of 0.2 MPa to 1.0 MPa. Effect of specific heat cause to increase flow measurement error as much as ratio of specific heat compare with reference gas. Pressure change cause to increase flowrate measurement deviation about $-0.2{\%}$ as the working pressure decreased 0.1 MPa.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.552-562
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• 2001

Measurement of average of heat transfer and friction coefficients were obtained with air flowing through electrically heated ducts having square, rectangular(aspect ration, 5), and triangular cross section for range of surface temperature from $540^{\circ}$to $1780^{\circ}$ R and Reynolds number from 1000 to 330,000. The results indicates that the effect of heat flux on correlations of the average heat transfer and friction coefficients is similar to that obtained for circular tubes in previous investigation and was nearly eliminated by evaluating the physical properties and density of the air a film temperature halfway between the average surface and fluid bulk temperatures, With the Nusselt and Reynolds numbers on the hydraulic diameter of the ducts, the data for the noncircular ducts could be represented by the same equations obtained in the previous investigation for circular tubes. Correlation of the average difference between the surface corner and midwall temperatures for the square duct was in agreement with predicted values from a previous analysis. However, for the rectangular and triangular ducts, the measured corner temperature was greater by approximately 20 and 35 percent, respectively, than the values predicted by analysis.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.91-98
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• 2010

The increasing of power and processing speed and miniaturization of central processor unit (CPU) used in electronics equipment requires better performing thermal management systems. A typical thermal management package consists of thermal interfaces, heat dissipaters, and external cooling systems. There have been a number of experimental techniques and procedures for estimating thermal conductivity of thin, compressible thermal interface material (TIM). The TIM performance is affected by many factors and thus TIM should be evaluated under specified application conditions. In compact packaging of electronic equipment the chip is interfaced with a thin heat spreader. As the package is made thinner, the coupling between heat flow through TIM and that in the heat spreader becomes stronger. Thus, a TIM characterization system for considering the heat spreader effect is proposed and demonstrated in detail in this paper. The TIM test apparatus developed based on ASTM D-5470 standard for thermal interface resistance measurement of high performance TIM, including the precise measurement of changes in in-situ materials thickness. Thermal impedances are measured and compared for different directions of heat dissipation. The measurement of the TIM under the practical conditions can thus be used as the thermal criteria for the TIM selection.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.107-107
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• 1999

Direct-contact condensation experiments of atmospheric steam and steam/air mixture on subcooled water flowing co-currently in a rectangular channel are carried out uszng an infrared thermal camera system to develop a temperature measurement method. The inframetrics Model 760 Infrared Thermal Imaging Radiometer is used for the measurement of the temperature field of the water film for various flow conditions. The local heat transfer coefficient is calculated using the bulk temperature gradient along the (low direction. It is also found that the temperature profiles can be used to understand the interfacial condensation heat transfer characteristics according to the flow conditions such as noncondensable gas effects, inclination effect, and flow rates.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.190-195
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• 2008

The objective of this research is to determine overall heat transfer coefficients (K-value) of exterior wall, floor, and roof of Nakseonjae, a Korean traditional residence via field measurement of transient heat flow and temperature difference across each envelope component. Heat flow sensors and T-type thermocouple were attached on the internal and the external surface of each building component, and real-time measurement data were collected for the three consecutive summer days. The K-values determined in this research showed good agreement with other results from open literature. Peak and annual thermal loads of the traditional residence estimated by a commercial energy simulation program were compared with those for a current apartment house. The traditional house showed lower annual cooling load than that of the current building. It may caused by the fact that the traditional building has less air-tight envelopes and no fenestration passing direct solar radiation into the space.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.52-59
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• 2001

Methods to measure and estimate transpiration of a forest composed of evergreen broad-leaved trees (Pasania edulis Makino) are studied. Heat pulse velocity has been measured along with soil moisture and micrometeorological factors at the Fukuoka Experimental Forest, the Research Institute of Kyushu University Forests in Fukuoka, Japan (33$^{\circ}$38'N, 130$^{\circ}$31'E, alt. 75m). Tree cutting measurement was conducted to convert the heat pulse velocity into sap flow and transpiration. A big leaf model to calculate transpiration and Interception loss is examined and the estimated values are compared with the measured values obtained from the heat pulse measurement. The results show that 1) Pasania edulis Makino posessing radial pore structure had relatively high water content and high heat pulse velocity even within the central part of the stem near the pith, 2) the heat pulse velocity was well correspond to the water uptake in the tree cutting measurement, 3) the estimation of sap flow based on the heat pulse velocity is accurate, and 4) the big leaf model using the parameters obtained from measurement of a portable photosynthesis system in one day in summer gives reasonable estimation of transpiration independent of seasons and weather.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.39-44
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• 2008

In this paper, heat transfer coefficients were measured in a channel with one side dimpled surface. The sphere type dimples were fabricated and the diameter and depth of dimple was 16mm and 4mm, respectively. Two channel heights of about 0.6 and 1.2 time of the dimple diameter, two dimple configuration were tested. The Reynolds numbers based on the channel hydraulic diameter was varied from 30000 to 50000. The improved hue detection based transient liquid crystal technique was used in the heat transfer measurement. Heat transfer measurement results showed that high heat transfer was induced downstream of dimples due to flow reattachment. Due to the flow recirculation on the upstream side in the dimple, the heat transfer coefficient was very low. As the Reynolds increased, the overall heat transfer coefficients also increased. With same dimple arrangement, the heat transfer coefficients and the thermal performance factor were higher for the lower channel height. As the distance between dimples became smaller, the overall heat transfer coefficient and the thermal performance factor were increased.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2624-2633
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• 1993

Mass transfer experiment by naphthalene sublimation method has great advantages in measurement of local transfer coefficients in the region of a three dimensional flow or for a model of complex geometry, which is considered to be very difficult with conventional heat transfer measurements. Mass transfer data obtained by naphthalene sublimation technique are converted to the heat transfer data through heat/mass transfer analogy. This analogy is valid for a simple or laminar flow, but new insight is needed when applying to a turbulent flow or complex flow such as separation, reattachment and recirculation, The purpose of this research is to investigate how geometries and flow conditions incorporate heat/mass transfer analogy. Mass transfer experiments are performed using naphthalene sublimation technique for a flat plate, a circular cylinder, and rectangular cylinders. And mass transfer data are compared with earlier heat transfer measurements for the same geometries. Usefulness of analogy relation between heat and mass transfer is examined with these results.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.595-600
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• 2001

Thermal mass flow meter(TMF) and thermal mass flow controller(MFC) were used to measure and to control the mass flow rate of gases. TMF and MFC were designed for specified working pressure and gas. For the case of different working pressure and gases, the flow rate measurement accuracy decreased dramatically. In this study, a TMF and MFC was tested with three different gases and pressure range from 0.2 MPa up to 1.0 MPa. Effect of specific heat causes to increase flow measurement error as much as ratio of specific heat compared with reference gas. Changing of pressure causes to increase flow rate measurement error about -0.2% as the working pressure decreased 0.1 MPa. Response time of MFC was below 3.12 s for the case of increasing of flow rate. But the response time was increased up to 6.92 s for the case of decreasing of flow rate. When the solenoid valve was fully closed, a initial delay time of output of MFC was increased up to 1.36 s.