액적분사를 이용한 에어컨 성능 향상

전창덕 한국교통대학교 2020 한국교통대학교 논문집 Vol.55 No.-

In the standard cooling conditions specified in KS C 9306, tests were performed for the case of no water injection and the case of water injection. In particular, in order to investigate the effect of the water injection position on the air conditioner performance, an experiment was conducted by changing injection position to the refrigerant inlet area of the condenser , the middle area, and the refrigerant outlet area. As a result of the experiment, the case of injecting water droplets to the refrigerant outlet area showed 6.2% COP improvement effect compared to the case of not spraying.

응축기 부분 액적 분사를 이용한 에어컨 성능 향상

전창덕 한국교통대학교 2021 한국교통대학교 논문집 Vol.56 No.-

In the standard cooling conditions specified in KS C 9306, tests were performed for the case of no water injection and the case of water injection at 70mm and 90mm distance in order to investigate the effect of the water injection location on the air conditioner performance. The refrigerant inlet area, the middle area, and the refrigerant outlet area of the condenser were considered as injection location. As a result of the experiment, the case of injecting water at 70mm distance on the refrigerant outlet area showed 7.1% COP improvement effect compared to the case of not spraying.

다채널 편평관의 응축 열전달 및 압력강하특성에 관한 실험

전창덕,정재원,이진호,Jeon, C.D.,Chung, J.W.,Lee, J.H. 대한설비공학회 1997 설비공학 논문집 Vol.9 No.3

In this study, an experiment was performed to investigate the characteristics of pressure drop and heat transfer of multi-channel tubes for automotive condenser using HFC-134a as an alternative refrigerant. The mass flux and inlet saturation pressure of the refrigerant were controlled, respectively, in the range of 200 to $500kg/m^2s$ and 1.0 to 1.6MPa. Pressure drop and heat transfer coefficient were compared with the previously proposed correlations and new correlations based on Traviss' correlation were suggested. Prediction of pressure drop and heat transfer coefficient based on the new correlations agrees with experimental results within ${\pm}9%$ and -18~+11%, respectively.

용접형 판형 열교환기의 응축특성에 관한 연구

全昌德 忠州大學校 1998 한국교통대학교 논문집 Vol.33 No.1

An experimental study on the characteristics of condensation heat transfer and pressure drop of brazed plate heat exchangers using R-22 has been performed. The experimental condition of mass flux and inlet saturation pressure of the refrigerant were in the range of 20 to 120kg/㎡s and 1.4 to 1.6Mpa respectively. The pressure drop and heat transfer coefficient were compared with the previously proposed correlations. The conclusion is as follows. As the mass flux increases, the trend of increase of both pressure drop and heat transfer coefficient was obtained. The more chevron angle increases, the lower the pressure drop and heat transfer coefficient are. For the case of applying subcooled state at inlet and outlet, scarcely pressure drop and heat transfer coefficient were influenced as inlet saturation pressure changes. The specific pressure drop was calculated and maximum specific pressure drop appears at chevron angle 20˚. When inlet and outlet flow was two-phase, pressure drop and heat transfer coefficient were decreased according to increase of inlet saturation pressure. When inlet state is superheated and outlet state is subcooled, pressure drop and heat transfer coefficient decrease as increase of inlet saturation pressure.

루우버휜형 열교환기의 열전달특성에 관한 실험적 연구

전창덕,홍주태,이진호 대한설비공학회 1996 설비공학 논문집 Vol.8 No.1

Experiment was performed to study the heat transfer characteristics in 27 kinds of 15 : 1 scale models of multi-louverred fin heat exchangers with a wide range of variables(R $e_{Lp}$ =100~1, 800, )>$L_p$/F)>$p$=0.3~0.9, $\theta$=20$^{\circ}$~40$^{\circ}$). Thermofoil heaters were used to heat the louver fins and the local average Nusselt number for each louver in the louver array was obtained at constant wall temperature conditions. Correlations are developed to predict the heat transfer characteristics and drag coefficients. Generally, the heat transfer characteristics in the multi-louvered fins is shown to be similar to those of the laminar heat transfer on a flat plate. As the Reynolds number, the louver pitch to fin pitch ratio)>$L_p$/F)>$p$and the louver angle($\theta$) increase respectively, the average Nusselt number increases, but the variation of average Nusselt number as a function of the louver angle is smaller than that as a function of the louver pitch to fin pitch ratio. In case of)>$L_p$/F)>$p$ <0.5, the average Nusselt number of the 3rd louver is especially lower than the others, it is expected that it is due to the flow structure such as a recirculation flow and a flow separation.

알루미늄 다채널관을 사용한 수랭식 열교환기 성능 연구(2)

전창덕 韓國交通大學校 2019 한국교통대학교 논문집 Vol.54 No.-

Comparative experiments were carried out to investigate the heating performance per unit volume of three water-cooled aluminum micro-channel heat exchangers under the heating condition(entering temperature 40±0.5oC, leaving temperature 45±0.5oC) described in KS B 6275. The following conclusions were obtained. The magnitude of heating capacity was in order of sample#1, sample#2, and sample#3. However, the heating capacity per unit volume was shown in the reverse order of sample#3, sample#2, and sample#1.

자동차 응축기용 다채널관의 압력강하 특성에 관한 연구

전창덕,정재원,이진호,강신형,Jeon, Chang Duk,Chung, Jae Won,Lee, Jinho,Kang, Shin Hyung 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.7

Experiment was performed to study the characteristics of pressure drop of multi-channel tubes for automotive condenser using HFC-134a. Single phase liquid and two phase flow pressure drop were measured in one rectangular plain and three micro-fin tubes with 10 channels. Data are presented for the following range of variables: mass flux(200 to $600kg/m^2s$), and inlet saturation pressure of the refrigerant(1.0 and 1.6MPa). For subcooled flow, pressure drops are 10% and 12% higher than that predicted by the Petukhov equation with hydraulic diameter respectively. Two-phase flow pressure drop are compared with the previously proposed correlations, and well predicted by modified correlation that was derived from Traviss correlation. and correlated within -30~+20%. Also experimental data are correlated within -56%~+18% by Webb's prediction method based on the equivalent mass velocity concept originally proposed by Akers et al.

대공간에서의 기류 및 온도분포에 관한 연구

전창덕,장성운 충주대 산업과학기술연구소 1997 産業科學論文集 Vol.5 No.-

This study considers the effects of internal air supply and exhaust system according to the change of locations in a large space. Especially PHOENICS CFD code was used. The velocity and temperature distribution were presented for various parameters such as air speed and heat source.

루우버휜형 열교환기의 유동 및 열전달 특성에 관한 수치해석

전창덕,이진호 연세대학교 대학원 1995 延世論叢 Vol.31 No.1

Abstract Low Reynolds k - ε turbulent modelling which has net been adopted on the study of characteristics on multi - louver fin heat exchanger has been conducted to study flow fields and heat transfer characteristics in the 15 : 1 scaled models based on multi - louver fin heat exchangers, those are being used in industry, in the range of various design parameters(Fp=20mm∼40mm, Lp=12mm∼18mm, θ = 20˚∼40˚)and inlet flow conditions(ReLP=100 1200) and mean flow angle, velocity profile, temperature profile, local average Nusselt number and so forth have been presented. By using of new flow efficiency defined by the concept including the effect of velocity, the relation with mean flow angle and heat transfer has been clarified because the definition of exisiting flow efficiency is not enough to make it clear. The best geometric condition for heat transfer is as follows ; Lp/Fp=0.9, θ =40˚. Generally the influence and occurrence of recirculation flow are increased as Reynolds mumber and louver angle increase but those are decreased as Lp/Fp increases.

R-22를 사용한 용접형 판형 열교환기의 응축 열전달 및 압력강하 특성에 관한 연구

전창덕,권오갑,이진호 대한기계학회 2001 大韓機械學會論文集B Vol.25 No.2