인터쿨러와 공랭식 응축기를 동시에 사용하는 냉방-냉동 겸용 캐스케이드 사이클에 대한 연구

김내현(Nae-Hyun Kim) 한국산학기술학회 2019 한국산학기술학회논문지 Vol.20 No.7

그간 캐스케이드 냉동 시스템에 대해서 열역학적 해석은 다수 수행되었으나 증발기, 응축기, 인터쿨러 등 부품해석을 통한 시스템 평가는 미진한 상태이다. 본 연구에서는 냉방 및 냉동 열교환기가 별도로 장착되어 있고 하부 사이클에 공랭식 응축기와 인터쿨러가 직렬로 연결되어 있는 캐스케이드 냉동 사이클에 대해 성능 해석을 수행하였다. 우선 증발기, 응축기, 인터쿨러 등 요소부품에 대해 모델링을 수행하고 R-410A를 사용하는 냉방 능력 8 kW, 냉동 능력 15 ㎾의 캐스케이드 냉동 사이클의 요소 부품의 – 상부 응축기, 하부 응축기, 냉방 증발기, 냉동 증발기, 인터쿨러, 압축기, 전자팽창변 – 설계를 수행하였다. 설계 사양에 대하여 외기 온도를 26℃에서 38℃로 변화시키며 해석을 수행한 결과 냉각 열량은 하부 증발기에서는 거의 일정하고 상부 증발기에서는 9% 감소, 인터쿨러에서는 63% 증가하였다. 한편 COP는 외기 온도의 증가에 따라 감소하였다. 인터쿨러가 작동하지 않는 사이클 대비 인터쿨러 사이클이 COP 측면에서 우위를 보였다. 또한 상부 응축기의 크기를 당초 설계치의 2배 증가시키면 하부 증발기 열량은 변함이 없는 반면 상부증발기 열량은 4% 증가하였다. 한편 상부 응축기의 크기 증가에 따라 상부 사이클의 COP는 증가하는 반면 하부 사이클의 COP는 큰 변화가 없다. 또한 하부 응축기 크기를 2.8배 증가시키면 상하부 증발기의 열량 변화는 거의 없고 인터쿨러의 열량만이 8% 감소하였다. 아울러 하부 사이클의 COP는 응축기의 크기가 증가함에 따라 다소 증가하였으나 상부 사이클의 경우는 그 변화가 미미하였다. Thermodynamic analysis of cascade refrigeration systems has attracted considerable research attention. On the other hand, a system evaluation based on thermodynamic analyses of the individual parts, including the evaporator, condenser, intercooler, expansion valve, etc., has received less attention. In this study, performance analysis was conducted on a cascade refrigeration system, which has an individual cooling and refrigeration evaporator, and equips the intercooler and air-cooled condenser in a series in a lower cycle. The thermo-fluid design was then performed on the major components of the system - upper condenser, lower condenser, cooling evaporator, refrigeration evaporator, intercooler, compressor, electronic expansion valve - of 15 ㎾ refrigeration, and 8 ㎾ cooling capacity using R-410A. A series of simulations were conducted on the designed system. The change in outdoor temperature from 26 C to 38 C resulted in the cooling capacity of the lower evaporator remaining approximately the same, whereas it decreased by 9% at the upper evaporator and by 63% at the intercooler. The COP decreased with increasing outdoor temperature. In addition, the COP of the cycle with the intercooler operation was higher that of the cycle without the intercooler operation. Furthermore, the increase in the upper condenser size by two fold increased the upper evaporator by 4%. On the other hand, the lower evaporator capacity remained the same. The COP of the upper cycle increased with increasing upper condenser size, whereas that of the lower cycle remained almost the same. When the size of the lower condenser was increased 2.8 fold, the intercooler capacity increased by 8%, whereas those of upper and the lower evaporator remained approximately the same. Furthermore, the COP of the lower cycle increased with an increase in the lower condenser. On the other hand, the change of the upper condenser was minimal.

루버휜 방열기형 고효율 인터쿨러 열설계

방광현(Kwang-Hyun Bang),김경규(Kyung-Kyu Kim),김상진(Sang-Jin Kim) 한국마린엔지니어링학회 2009 한국마린엔지니어링학회 학술대회 논문집 Vol.2009 No.-

An high-efficiency intercooler for high-power Diesel engine power pack has two separate cooling circuits of high-temperature and low-temperature, thus three fluid paths of high and low temperature coolants and the charge air are involved in this type of heat exchanger. A cell-by-cell thermal rating method is employed to design and calculate the thermal rating of the intercooler. A model intercooler has been designed and fabricated and the measurement of thermal performance of the model intercooler shows good agreement with the design calculations.

RESEARCH ON THE INTEGRATED INTERCOOLER INTAKE SYSTEM OF TURBOCHARGED DIESEL ENGINE

Sheng Liu,Yangjun Zhang 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.2

In order to improve the compactness and performance of the intake system of turbocharged diesel engines, an integrated intercooler intake system is provided. Porous media computational fluid dynamics (CFD) model is used to analyze the flow and heat exchange performance of the integrated intercooler. The flow resistance, pressure fluctuation, temperature and pressure distribution of integrated intercoolers with different structures are compared by CFD simulation. The simulation results show that the best performance is achieved by the structure with central air intake with a baffle. Experimental study has been carried out to investigate the steady and transient performance of diesel engine with the original or integrated intercooler intake system. The test results show that with the use of the integrated intercooler intake system, the brake specific fuel consumption can be reduced by 5.9 g/kW·h at the rated condition, and the response time is reduced by 20.4 % under medium speed loading process.

2단압축 이산화탄소 사이클의 냉방성능 향상 특성에 대한 실험적 연구

조홍현,이호성,김용찬 대한설비공학회 2006 설비공학 논문집 Vol.18 No.10

A CO2 system using the two-stage compression cycle was tested by varying 1st-2nd compressor frequencies in the cooling mode. To improve the cooling performance of the two-stage compression CO2 cycle, the following cycle options were applied: a basic cycle, a cycle with an intercooler, a cycle with an IHX(internal heat exchanger), and a cycle with an intercooler and IHX. The cycle with the intercooler-IHX showed the highest cooling capacity improvement among the cycle options at all compressor frequencies. The cycle with the intercooler, the cycle with the IHX, and the cycle with the intercooler-IHX improved the cooling COP by 7, 12, and 15%, respectively, over the basic CO2 cycle when the compressor frequencies for the first and second compressors were 50Hz and 30Hz, respectively. In addition, the applications of the selected cycle options enhanced system reliability.

소형 선박용 디젤엔진의 수냉식 인터쿨러 해석 연구

양영준(Young-Joon Yang),심한섭(Han-Sub Sim) 한국기계가공학회 2014 한국기계가공학회지 Vol.13 No.5

This study was carried out to improve the design of an intercooler for a small marine diesel engine. Diesel engines for small marine ships have mainly been developed by changing the structure of the vehicle engine. Sea water was most commonly used in the intercooler of small marine diesel engines to cool the hot air compressed by the turbocharger. In this study, the intercooler is modeled and simulated using STAR-CCM+ in order to find optimal data for the design of an intercooler. In the results, the temperature differences between the data from a numerical analysis and experimental data were 0.38℃ in the hot air outlet and 3.63℃ in the cooling water outlet. Therefore, it was confirmed that both analysis and experimental results need to be considered when designing an intercooler. A closer degree of similarity in the two datasets can improve the confidence in the design of these intercoolers.

디젤엔진의 터보랙에 대한 실험적 연구

박성호(Sungho Park),장길상(Kilsang Jang),이준호(Joonho Lee),오광철(Kwangchul Oh),고성석(Sungsuk Ko),최재권(Jaekwon Choi),지용준(Yongjun Jee) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

Improving the performance and the fuel economy of an engine, the reduction of engine size is considered by using a turbocharger or supercharger. But the turbocharged engines have worse transient response than the naturally aspirated engines because it takes a few seconds to get the turbocharger rotate up to high speed. So many technologies are developed to improve turbocharger response: VGT, Twin turbocharger, water-cooled intercooler, and so on. And there are many researches to analyze turbocharger transient phenomenon: optimizing the size of a turbocharger, flow capacity, efficiency, and moment of inertia. This research deals with the transient response of a diesel engine with variable geometry turbocharger and water-cooled intercooler. And it’s focused on intercooler size, WCAC pipe length, and cooling water temperature of the water-cooled intercooler.

터보과급 가솔린 기관의 중간냉각 효과

金 進 慶一大學校 1999 論文集 Vol.16 No.5

Turbocharger drives turbin using exhaust gas as a power source, it compresses inlet air by driving one line compressor and so it charges air mass flow combustion chamber. However turbocharged gasoline engine is easy to making knok as the gas pressure & temperature in combustion chamber is hightening and it causes also thermal changes in engine structure for thermal stress from combustion gas of high temperature & high pressure. First problems in turbocharged gasoline engines different from disel engine is knock occurrence and it makes charge limit. Knock occurrence can be constrainted by retarding spark time. Further studies are needed about knock limit compression ratio, knock limit spark advance and intercooling effect to knock limit compression ratio for determining compression ratio in design of turbocharged gasoline engines because knock limit changes according to change of compression ratio. This study purpose fundamental design data secure determining compression ratioof turbocharged gasoline engine. We determined knock limit compression ratio to charge pressure change. This result data adapted in relation equation about knock limit compression ratio & knock limit charge pressure ratio based on autoignition theory. Adapting result can be classified for without & with intercooler. Case of intercooling gains charge pressure rise as well as maximum engine power for intercooling reduces knocking and it akes engine drive limit farther. Knock limit compression ratio to charge pressure ratio is also glossified in case of intercooling. Consequently, it is clear in this study that if turbocharged gasolin engine is intercooled, density ratio augmentation & knock limit compression ratio magnification of turbocharged gasoline engine will increase the power of engine. Therefore, we can suggest fundamental design sources for detenning compression ratio of turbocharged gasoline engine.

터보 차져와 인터쿨러를 장착한 디젤기관의 시뮬레이션 연구

한영출,백두성,류규현,오용석,박만재 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.4

Studies on the turbocharger itself or various aspects generated from turbocharged engine have been made. However, only a few researches have been made on the performance for the natural aspirated engine equipped with the turbocharger and the intercooler. In this study, the performance prediction program based on turbocharger theory is developed for simu-lation which may reduce the cost and the trial-and-error time. The program is verified with the experimental results for 11,000cc diesel engine with the turbocharger and the intercooler. Also, various factors which are invisible in experiment are predicted using this program.

LP EGR용 인터쿨러 내식소재 선정에 대한 실험적 연구

이동석(Dong-suk Lee),오광헌(Kwang-hun Oh),정순안(Sun-an Jeong),이찬우(Chan-woo Lee) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5

In the LP EGR system, acidic condensate is formed on the inner surface of the intercooler. It was reported that acetic acid, formic acid, sulfuric acid, nitric acid and the like were detected in this condensate. In order to increase the corrosion resistance of intercoolers to the acidic environment, the 5-layer clad material was examined instead of the existing 3-layer clad materials. The 5-layer clad material is a multilayer clad material having a sacrificial layer between the filler alloy layer for brazing and the core alloy. In particular, we wanted to compare the corrosion resistance characteristics according to the difference in composition of the alloy constituting the sacrificial layer. In this study, the pressure resistance and corrosion resistance assessment were performed which is generally selected for development of intercoolers. And corrosion resistance to acidic environments was evaluated using solutions of the VDA K3.2 standard. This test method was proposed by VDA for evaluating corrosion characteristics of condensate generated in the LPEGR system. The 5-layer clad materials met the general requirements for pressure and corrosion characteristics of the intercooler. In addition, the 5-layer clad materials were shown significant characteristics under the acid corrosion test than the 3-layer clad material, and the corrosion life of the intercooler is expected to increase in the LP EGR system.

커먼레일 디젤기관의 인터쿨러 대체를 위한 볼텍스 튜브 적용 특성에 관한 실험 연구

임석연(Seokyeon Im),이호길(Hokil Lee),정영철(Youngchul Jung),최두석(Dooseuk Choi),류정인(Jeongin Ryu) 한국자동차공학회 2009 한국 자동차공학회논문집 Vol.17 No.2

An object of this study is to confirm application characteristics of the vortex tube apparatus for substitution of the intercooler in a common-rail diesel engine. The turbo pressure, the intake air mass flow rate and the charging air cooling ratio of the intercooler were measured in an experimental engine. The vortex tube apparatus was made after confirmation of the geometric phenomena in fundamental experiments. The vortex tube designed with fundamental data was applied to a conventional common-rail diesel engine instead of the intercooler. Its application characteristics, engine performances and emissions were investigated. From this experimental results, we suggested the vortex tube can be applied to a conventional common-rail diesel engine throughout extra complement. We can also expect the higher cooling effect, if we consider the application of the vortex tube in supercharging diesel engine without the intercooler.