• Title/Summary/Keyword: Heat exchanger separator

Search Result 19, Processing Time 0.039 seconds

A Study on the Forming Process of High-strength Aluminum Sheet for Electric Vehicle Heat Exchanger Separator Through Parametric Analysis (인자 분석을 통한 전기차 열교환기 분리판용 고강도 알루미늄 판재 성형 연구)

  • Jung, S.H.;Yang, J.H.;Kim, Y.B.;Lee, K.J.;Kim, B.H.;Lee, J.S.;Bae, G.H.
    • Transactions of Materials Processing
    • /
    • v.31 no.2
    • /
    • pp.57-63
    • /
    • 2022
  • The current study performed formability analysis of a heat exchanger separator for an electric vehicle to apply a high-strength aluminum sheet based on parametric analysis. Mechanical properties for sheet metal forming simulation were evaluated by tensile test, bulge test, and Nakajima test. Two-stage crash forming was established by considering the mass production process using conventional low-strength aluminum sheets. In this study, FEM for the two-stage forming process was conducted to optimize the corner radius and height for improving the formability. In addition, the possibility of a one-stage forming process application was confirmed through FEM. The prototype of the sample was manufactured as FEM results to validate the parametric analysis. Finally, this result can provide a one-stage forming process design method using the high-strength aluminum sheet for weight reduction of a heat exchanger separator for an electric vehicle.

Performance Analysis on a Multi-Pass Multi-Branch Heat Exchanger According to Pass Arrangement (다패스 다분지 열교환기의 패스 수에 따른 성능 분석)

  • Kim Min-Soo;Lee Kwan-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.30 no.8 s.251
    • /
    • pp.741-748
    • /
    • 2006
  • This paper numerically investigates the effects of pass arrangement on the flow distribution characteristics and the performance of a multi-pass multi-branch heat exchanger. Four cases of pass arrangement (2, 4, 6, 8 pass) are chosen to select a proper pass arrangement. A JF factor is used as an evaluation characteristic value to consider the heat transfer and the pressure drop. The present results indicate that 4-pass heat exchanger shows the best performance, and the design parameters in 4-pass heat exchanger are optimized. The design parameters are the locations of the inlet, outlet and separator, and are optimized using a response surface methodology. The JF factor of the optimum model is increased by about 9.3%, compared to that of the reference model (2-pass heat exchanger).

Thermal and flow analysis for the optimization of a parallel flow heat exchanger (평행류 열교환기의 열.유동 해석 및 최적화)

  • Lee, Gwan-Su;Jeong, Ji-Wan;Yu, Jae-Heung
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.22 no.2
    • /
    • pp.229-239
    • /
    • 1998
  • The present paper examines the thermal and flow characteristics of a parallel flow heat exchanger and investigates the effects of the parameters on thermal performance by defining the flow nonuniformity. Thermal performance of a parallel flow heat exchanger is maximized by the optimization using Newton's searching method. The flow nonuniformity is chosen as an object function. The parameters such as the locations of separator, inlet, and outlet are expected to have a large influence on thermal performance of a parallel flow heat exchanger. The effect of these parameters are quantified by flow nonuniformity. The results show that the optimal locations of inlet and outlet are 19.73 mm and 10.9 mm, respectively. It is also shown that the heat transfer increases by 7.6% and the pressure drop decreases by 4.7%, compared to the reference model.

A Study on the Characteristics of Refrigeration System Installed with Precooler, and Liquid-Vapor Separator after Expansion Device (과냉각기와 팽창장치 후 액기분리기를 적용한 냉동시스템 성능특성 연구)

  • Yun, Sang-Kook
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.35 no.1
    • /
    • pp.40-45
    • /
    • 2011
  • The purpose of research is to understand the characteristics of refrigeration system having a liquid-vapor phase separator after expansion device and precooling heat exchanger. After expansion process of typical refrigerant of freezer, R134a, the cold vapor of the expanded refrigerant mixture is separated in the liquid-vapor separator and introduced in the precooling heat exchanger to enable the liquid refrigerant to be subcooled. The analysis results showed that the increasing rate of refrigeration capacity and COP can be 8.6% and 1.4%, each. The cause of these performance improvements is due to the difference of the slope of saturated vapor and saturated liquid lines in Mollier diagram of refrigerant.

An Experimental Study of Operating Characteristics on Fouling Auto Removal Apparatus of Multi Pass Type Heat Exchanger using Ejector (이젝터를 이용한 다관식 열교환기 파울링 자동제거장치의 구동특성에 관한 실험적 연구)

  • Kim, J.D.
    • Journal of Power System Engineering
    • /
    • v.13 no.6
    • /
    • pp.63-69
    • /
    • 2009
  • The experiment was performed to check operating characteristics of fouling auto removal apparatus for multi pass type heat exchanger using ejector. The results showed as following. The ejector suction flow rate increased with the head of operating pump of ejector. Proper suction flow rate showed $7.2{\sim}10.2m^3/h$ for ball collection in case of pump head 35~50m. The head of ejector outlet pipe is below 4.1m in case of 40m, the head of operating pump of ejector to confirm ejector suction flow rate 8.4m3/h. Lattice space of ball separator is allowed 6~10.3mm in ranges of ball diameter are 15~25mm and when mass flow of cooling water is 3.0m/sec. Average of passing time of balls is 1.2~2.8sec depend on the velocity of flow and the size of balls.

  • PDF

Simulation of a geothermal power generation system using the Kalina cycle (칼리나 사이클을 이용한 지열발전 시스템의 시뮬레이션)

  • Chang, Ki-Chang;Baik, Young-Jin;Kim, Min-Sung;Lee, Young-Soo;Park, Seong-Ryong;Ra, Ho-Sang
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2008.05a
    • /
    • pp.626-629
    • /
    • 2008
  • In this study, a geothermal power generation system using the Kalina cycle was investigated by the simulation method. The Kalina cycle system can be used for the utilization of a low-temperature heat sources such as geothermal and industrial waste heat that are not hot enough to produce steam. The sea/river water can be considered as a cooling media. A steady-state simulation model was developed to analyze and optimize its performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump were modelled by an isentropic efficiency, while a condenser, an evaporator and a regenerative heat exchanger were modeled by UA-LMTD method with a counter-flow assumption. The effect of the ammonia fraction at the separator inlet on the cycle performance is investigated in detail.

  • PDF

Development of Remote Reld Testing Technique for Moisture Separator & Reheater Tubes in Nuclear Power Plants (원자력발전소 습분분리재열기 튜브 원격장검사 기술 개발)

  • Nam, Min-Woo;Lee, Hee-Jong;Kim, Cheol-Gi
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.28 no.4
    • /
    • pp.339-345
    • /
    • 2008
  • The heat exchanger tube in nuclear power plants is mainly fabricated from nonferromagnetic material such as a copper, titanium, and inconel alloy, but the moisture separator & reheater tube in the turbine system is fabricated from ferromagnetic material such as a carbon steel or ferrite stainless steel which has a good mechanical properties in harsh environments of high pressure and temperature. Especially, the moisture separator & reheater tubes, which use steam as a heat transfer media, typically employ a tubing with integral fins to furnish higher heat transfer rates. The ferromagnetic tube typically shows superior properties in high pressure and temperature environments than a nonferromagnetic material, but can make a trouble during the normal operation of power plants because the ferrous tube has service-induced damage forms including a steam cutting, erosion, mechanical wear, stress corrosion cracking, etc. Therefore, nondestructive examination is periodically performed to evaluate the tube integrity. Now, the remote field testing(RFT) technique is one of the solution for examination of ferromagnetic tube because the conventional eddy current technique typically can not be applied to ferromagnetic tube such as a ferrite stainless steel due to the high electrical permeability of ferrous tube. In this study, we have designed RFT probes, calibration standards, artificial flaw specimen, and probe pusher-puller necessary for field application, and have successfully carry out RFT examination of the moisture separator & reheater tube of nuclear power plants.

A Study on the Determination of Mixed Refrigerant for the Joule-Thomson Cryocooler (극저온 Joule-Thomson 냉동기용 혼합냉매 결정에 관한 연구)

  • 이경수;장기태;정상권
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.12 no.10
    • /
    • pp.901-907
    • /
    • 2000
  • The conceptual determination of mixed-refrigerant (MR) for a closed Joule-Thomson cryocooler is described in this paper. The thermodynamic cycle design was mainly considered to develop a cryocooler by using a compressor of domestic air-conditioning unit. The target cooling performance of the designed cryocooler is 10 W around 70 K with less than 5 kJ/kg enthalpy rise. The systematic approach of choosing a proper refrigerant among 20 different kinds of mixture for such cryogenic temperature was introduced in detail. The main components of the cryocooler are compressor, evaporator, oil separator, after-cooler, counterflow heat exchanger, and J-T expansion device. Due to the limitation of the compressor operation range, the temperature after the compression was limited below $117^{\circ}C$ (390 K) and the temperature before compression was restricted above $5^{\circ}C$ (278 K). 20 atm of discharging pressure (high pressure) and less than 3 atm suction pressure (low pressure) were the design conditions. The inlet temperature of a counterflow heat exchanger in the high Pressure side was about 300 K. The proper composition of the mixed refrigerant for the designed J-T cryocooler is 15% mol of$ N_2, 30% mol of $CH_4,\; 30% mol\; of C^2H^ 6,\; 10%\; mol\; of\; C_3H_8\; and \;15%\; mol\; of\; i-C_4H_10$.

  • PDF

An Experimental Study of Cryochiller System Using Autocascade (오토캐스케이드 방식을 적용한 극저온 칠러 시스템의 실험적 연구)

  • Cha, Dong-an;Kwon, Oh-kyung;Yun, Jae-ho;Kim, Dae-yeol
    • Proceedings of the KSME Conference
    • /
    • 2007.05b
    • /
    • pp.1980-1985
    • /
    • 2007
  • The purpose of this study is to investigate the performance of an autocascade refrigeration system using the refrigerant mixtures of R-134a(64${\sim}$72wt%), R-23(20${\sim}$25wt%) and R-14(8${\sim}$12wt%) as working fluids by experiment. The experimental apparatus consisted of a autocascade system with a compressor, condenser, evaporator, gas-liquid separator and cascade condenser, etc. Two main causes to this failure were considered as follows. First, the pressure ratio in the compressor was extremely increased at the beginning of the experiment. Second, the outlet temperature in compressor was higher than its limited temperature. For a stable operation of the compressor, a portion of the mixed refrigerant was by-passed at the inlet of the heat exchanger and transferred directly to the suction of the compressor in the modified system. The experimental parameters were changed weight of R-134a(1800g, 2800g), R-23(700, 800, 900g) and R-14(300, 400, 500g). The results showed that the best performance in case of R-134a of 2800g, R-23 of 900g and R-14 of 500g.

  • PDF

Performance Characteristics of OTEC(Ocean Thermal Energy Conversion) Power Cycle with Vapor-Liquid Ejector (증기-액 이젝터를 적용한 해양온도차발전 시스템의 성능 특성)

  • Yoon, Jung-In;Son, Chang-Hyo;Kim, Hyeon-Uk;Ha, Soo-Jung;Lee, Ho-Saeng;Kim, Hyun-Ju
    • Journal of Power System Engineering
    • /
    • v.18 no.5
    • /
    • pp.88-93
    • /
    • 2014
  • In this paper, the performance analysis of condensation and evaporation capacity, turbine work and efficiency of the OTEC power system using vapor-liquid Ejector is presented to offer the basic design data for the operating parameters of the system. The working fluid used in this system is $CO_2$. The operating parameters considered in this study include the vapor quality at heat exchanger outlet, pressure ratio of ejector and inlet pressure of low turbine, mass flow ratio of separator at condenser outlet. The main results were summarized as follows. The efficiency of the OTEC power cycle has an enormous effect on the mass flow ratio of separator at condenser outlet. With a thorough grasp of these effects, it is possible to design the OTEC power cycle proposed in this study.