Computer Simulation of an Automotive Air-Conditioning in a Transient Mode

Oh, Sang-Han,Won, Sung-Pil The Society of Air-Conditioning and Refrigerating 2002 International Journal Of Air-Conditioning and Refr Vol.10 No.4

The cool-down performance after soaking is very important in an automotive air-conditioning system and is considered as a key design variable. Therefore, transient characteristics of each system component are essential to the preliminary design as well as steady-state performance. The objective of this study is to develop a computer simulation model and ostinato theoretically the transient performance of an automotive air-conditioning system. To do that, the mathematical modelling of each component, such as compressor, condenser, receiver/drier, expansion valve, and evaporator, is presented first of all. The basic balance equations about mass and energy are used in modelling. For detailed calculation, condenser and evaporator are divided into many sub-sections. Each sub-section is an elemental volume for modelling. In models of expansion valve and compressor, dynamic behaviors are not considered in this analysis, but the quasisteady state ones are just considered, such as the relation between mass flow rate and pressure drop in expansion device, polytropic process in compressor, etc. Also it is assumed that there are no heat loss and no pressure drop in discharge, liquid, and suction lines. The developed simulation model is validated by comparing with the laboratory test data of an automotive air-conditioning system. The overall time-tracing properties of each component agreed well with those of test data in this case.

A new component map generation method for gas turbine adaptation performance simulation

Qingcai Yang,Shuying Li,Yunpeng Cao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4

The accuracy of component maps significantly affects gas turbine performance simulation results. Unfortunately, the information in component maps is usually insufficient to performance simulation. In this paper, a new compressor map generation method is presented with the primary objective of improving the accuracy of the gas turbine performance simulation model under insufficient information. In this method, the compressor map is first generated as an initial map according to the operating points determined by a set of steady-state operating data, and the coefficients that determine the shape of the compressor map are analyzed and tuned through a multi-objective optimization scheme to match multiple sets of transient data. To verify the validity of the new method, an LM2500 compressor map from the public literature was generated and the results were compared with those of existing fitting methods. Furthermore, the new map generation method, developed in Simulink, was implemented in a dynamic gas turbine model and tested in off-design steady-state and transient conditions. The results showed that the method is able to overcome the shortcomings of the existing methods and to effectively improve the accuracy of the gas turbine performance model under insufficient information.

차량 운전 특성에 따른 연비성능 시뮬레이션

송준형(Junhyung Song),김덕진(Deokjin Kim),이천환(Chunhwan Lee),이춘범(Chunbeom Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

This paper discussed conditions of acceleration through a velocity profile of vehicle modeling by using the simulation program in order to analyze the characteristic of fuel efficiency according to the pattern of acceleration and vehicle driving. The experiment was performed under the condition of the slope of acceleration, the change of velocity, and the slope change of velocity. Then, the basic performance of vehicle and the characteristic of driving pattern were analyzed through simulating. Through analyzing simulating results according to the initial change of acceleration, we could see that the amount of fuel consumption was little when the accelerated motion was increased gradually, but the good efficiency was shown when the ability of initial acceleration was better with consideration of fuel consumption per distance, while there are various routes under the condition of reaching the goal velocity in the same time. Through analyzing simulating results according to the driving pattern, we could see that the generating power was lower, but the fuel efficiency was better when the accelerated motion was increased gradually.

2-spool 선박용 가스터빈 엔진의 동적 시뮬레이션 수학모델 개발

차승우,기자영,손나영,김동진,심재순,김명환,박상균 한국마린엔지니어링학회 2019 한국마린엔지니어링학회지 Vol.43 No.9

In this study, a dynamic behavior simulation mathematical model of 2-spool marine gas turbine engine is developed. Specifically, we develop an engine performance model using data provided by an engine manufacturer for ease of integration with other component performance models of ship propulsion systems and for fast calculation processing speed. SIMULINK is used for dynamic behavior modeling, and performance data and steady-state convergence interval data are compared to verify the mathematical model. In addition, performance analysis of the transient mode, which increases from engine stop to maximum output, is performed and compared with manufacturer data. A simulation of the engine behaviors in terms of acceleration, deceleration, and stopping to stop, idling, and maximum output is performed using the verified model. 본 연구에서는 2-Spool 선박용 가스터빈 엔진의 동적거동 모사 수학 모델을 개발하였다. 선박 추진시스템의 다른구성품 성능 모델과의 통합의 용이함, 빠른 계산처리 속도를 위해 엔진 제작사로부터 제공받은 데이터를 이용하여 엔진성능 모델을 개발하였다. 동적 거동 모델링에는 SIMULINK를 사용하였으며, 수학적 모델의 검증을 위해 정상상태 수렴구간에서의 성능데이터와 제작사 제공 데이터를 비교하였다. 또한 엔진의 정지 상태에서 최대 출력까지 증가하는 천이모드의 성능해석을 수행하여 제작사 데이터와 비교하였다. 검증된 모델을 이용하여 정지, 공회전까지의 가속, 최대 출력까지의 가속, 감속 및 정지의 동작 거동 시뮬레이션을 수행하였다.

Transient Engine Test Bed를 이용한 가속성능향상에 관한 연구

김동수(Dongsoo Kim),안태식(Taeshik Ahn),이상수(Sangsu Lee),이문식(Moonsig Lee) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Performance Analysis of Sensible and Latent Energy Recovery System for Thermally Controlled Facility

Park, Byung-Kyu,Kim, Moo-Geun,Kim, Geun-Oh The Society of Air-Conditioning and Refrigerating 2001 International Journal Of Air-Conditioning and Refr Vol.9 No.4

Simulation was conducted using TRNSYS to evaluate the thermal performance of a facility. This facility has a condensing-type heat exchanger which is able to recover the latent energy for the purpose of reducing the heating energy in winter. The boiler and chiller are selected based on the annual peak loads and controlled to maintain the facility at the set temperature of 14~$17^\circ{C}$. Supplied energy by the boiler and recovered energy by the heat exchanger were calculated as a function of number of pass through heat exchanger, kind of fuel and hot water velocity. Simulation results show that about 20% of the total heating load can be recovered by the heat exchanger and the amount of latent heat is increasing with the number of pass. This means that the efficiency of the waste energy recovery system can be increased by using a condensing-type heat exchanger rather than a traditional sensible heat exchanger.

화재상황에서의 학교건축물 구조안전성 변화 예측 기법 연구

안아영(An, Ah Young),김희선(Kim, Hee Sun),신영수(Shin, Yeoung Soo) 대한건축학회 2015 大韓建築學會論文集 : 構造系 Vol.31 No.8

The purpose of this study was to find variables effecting on fire simulation and to evaluate safety of the structural members based on temperature distributions. Toward that goal, fire simulation, transient heat transfer analysis, structural safety evaluation are carried out sequentially using Fire Dynamics Simulator (FDS), ABAQUS 6.10-3, MIDAS 785, respectively. Fire simulation is performed on a 5-story building used for a school, located in Seoul, South Korea. The results of this study were as follows; structural members are exposed spatially non-uniform temperatures which can cause significant eccentric deformation and acceleration of structural damages. Using non-uniform temperatures, reduction ratios of structural performance in structural members are deducted.

마이크로 가스터빈의 동특성해석을 위한 프로그램 개발

김민재(Min jae Kim),김정호(Jeong ho Kim),김동섭(Tong seop Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

An accurate simulation of operating behavior is an essential part in developing gas turbine engines. It reduces development time and cost. This paper describes a program which is capable of simulating transient operation of micro gas turbines. The program is still being developed and this paper introduces its structure and some examples of simulating dynamic responses and transient operation of a micro gas turbine under development. The program is coded with MATLAB. The program includes mass and energy balances and operating characteristics of each component, rotational inertia of shaft and thermal inertia of recuperator. Firstly, simple dynamic responses of the engine were examined to validate dynamic modeling. Then, controlled operation of the engine during load change was simulated and the trends of engine behavior were compared with those of a commercial engine.

UTC Solarwall 건축물 통합시스템 년간 에너지 성능평가 Simulation 기술에 관한 연구

박준언(Jun-Un Park),이의준(Eye-Joon Lee),정모(Mo Chung) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.9

UTC(Unglazed Transpired Collector) Solarwall Solar Air Heating(SAHS) systems have unique advantages for space heating and tempering ventilation air over the conventional collector system such as flat plate collector and vacuum collector. SAHS can improve radiation loss due to nonglazed component and convectional loss due to enhanced plate surface configuration. Heating energy and its equivalent green house emission performance can be improved from the use of this solar air heating system. A consistent method to estimate annual EPI(Energy Performance Index), energy savings per unit area, has been required to be implemented in many IPMVP(International Performance Measurement Verification Protocol) and ESCO(Energy Service Company)project. This study is to develop a simulation and verification method to estimate the annual energy savings in future ESCO solar wall project.

현장 타설 에너지파일을 적용한 지열 히트펌프 시스템의 성능 예측

손병후(Byonghu Sohn),정경식(Kyung-Sik Jung),최항석(Hangseok Choi) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.1

The aim of this study is to evaluate the performance of the GHP system with 45 cast-in-place energy piles(CEP) for a commercial building. In order to demonstrate the feasibility of a sustainable performance of the system, transient simulations were conducted over 1-year and 20-year periods, respectively. The 1-year simulation results showed that the maximum and minimum temperatures of brine returning from the CEPs were 23.91℃ and 6.66℃, which were in a range of design target temperatures. In addition, after 20 years’ operation, these returning temperatures decreased to 21.24℃ and 3.68℃, and finally reached to stable state. Annual average extraction heat of cast-in-place energy piles was 94.3 MWh and injection heat was 65.7 MWh from the 20 years of simulation results. Finally, it is expected this GHP system can operate with average heating SPF of more than 3.45 for long-term.