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( Wee Kyong Kim ),( Thomas Aicher ) 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.2
The influences of geometrical parameters on the shell side heat transfer in shell-and-tube heat exchangers are investigated by experiments using 32 different test heat exchangers. The test heat exchangers differ by number of tubes, length, shell and tube diameter, nozzle diameter and tube pitch. From the experimental results it can be confirmed that the influence of the tube pitch is small enough to be neglected in shell-and-tube heat exchangers used in real processes. The heat transfer rate of the longitudinal flow can be calculated from the correlation for turbulent flow in concentric annular ducts by inserting the porosity instead of the ratio of tube to shell diameter. The influence of the cross flow in the nozzle region increases with decreasing length of the heat exchangers. The heat transfer coefficients in the nozzle region are ditermined by comparing the overall heat transfer coefficients of the heat exchangers with that calculated from the correlation for the longitudinal flow. The results show that the heat transfer coefficient in the nozzle region is 40% greater than that in the parallel region if the length of the apparatuses is about 30 times the hydraulic diameter. A new correlation suitable for predicting the heat transfer coefficient is presented, which consists of a superposition of the Nusselt number for the flow in the nozzle region and that for the longitudinal flow.
EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER IN SHELL-AND-TUBE HEAT EXCHANGERS WITHOUT BAFFLES
Kim, Wee Kyong,Aicher, Thomas 한국화학공학회 1997 Korean Journal of Chemical Engineering Vol.14 No.2
The influences of geometrical parameters on the shell side heat transfer in shell-and-tube heat exchangers are investigated by experiments using 32 different test heat exchangers. The test heat exchangers differ by number of tubes, length, shell and tube diameter, nozzle diameter and tube pitch. From the experimental results it can be confirmed that the influence of the tube pitch is small enough to be neglected in shell-and-tube heat exchangers used in real processes. The heat transfer rate of the longitudinal flow can be calculated from the correlation for turbulent flow in concentric annular ducts by inserting the porosity instead of the ratio of tube to shell diameter. The influence of the cross flow in the nozzle region increases with decreasing length of the heat exchangers. The heat transfer coefficients in the nozzle region are ditermined by comparing the overall heat transfer coefficients of the heat exchangers with that calculated from the correlation for the longitudinal flow. The results show that the heat transfer coefficient in the nozzle region is 40% greater than that in the parallel region if the length of the apparatuses is about 30 times the hydraulic diameter. A new correlation suitable for predicting the heat transfer coefficient is presented, which consists of a superposition of the Nusselt number for the flow in the nozzle region and that for the longitudinal flow.
Junior College or the NCAA: The Case of a U.S. Women’s Tennis Team with No U.S. Players
B. Nalani Butler,Thomas J. Aicher,Benjamin Wieber 글로벌지식마케팅경영학회 2020 Journal of Global Sport Management Vol.5 No.1
United States (U.S.) colleges and universities attract thousands of international student-athletes from around the world. This research study presented data on a qualitative exploratory case study (Yin, 2009) in which participants of a U.S. junior college women’s tennis team were observed and interviewed. Participants were asked questions about their motivations to come to the U.S. to play intercollegiate tennis and obtain a degree in higher education. The world systems theoretical framework was used to examine the motivations of the participants in this study, who chose to pursue tennis at the junior college level in the U.S. Please note that this was an exploratory qualitative case study with a small sample size of participants and responses from participants reflect the motivations of a few international student-athletes who participated in this study.