ML11356A402
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| Site: | Indian Point  |
| Issue date: | 09/12/2008 |
| From: | Kim K, Lim J, Yoon J Korea Power Engineering Co, Kyungwon University |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
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| RAS 21625, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
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RIV000051 Date Submitted: December 22, 2011 Journal of Mechanical Science and Technology Journal of Mechanical Science and Technology 22 (2008) 2218~2227 www.springerlink.com/content/1738-494x DOI 10.1007/s12206-008-0912-9 Thermal fatigue estimation due to thermal stratification in the RCS branch line using one-way FSI scheme Kwang-Chu Kim1, Jong-Han Lim2 and Jun-Kyu Yoon2,*
1 Korea Power Engineering Company, Inc., Yongin, Gyeonggi, Republic of Korea 2
Department of Mechanical & Automovtive Engineering, Kyungwon University, Seongnam, Gyeonggi, Republic of Korea (Manuscript Received June 26, 2007; Revised April 15, 2008; Accepted September 12, 2008)
Abstract The scheme and procedure for thermal fatigue estimation of a thermally stratified branch line were developed. One-way FSI (fluid and structure interaction) scheme was applied to evaluate the thermal stratification piping. Thermal flow analysis, stress analysis and fatigue estimation were performed in serial order. Finally, detailed monitoring locations and mitigation scheme for the integrity maintenance of piping were recommended. All wall mesh and transient tem-perature distribution data obtained from the CFD (computational fluid dynamics) analysis were directly imported into the input data of stress analysis model without any calculation for heat transfer coefficients. Cumulated usage factors for fatigue effect review with nodes were calculated. A modified method that combines ASME Section III, NB-3600 with NB-3200 was used because the previous method cannot consider the thermal stratification stress intensity. As the results of evaluation, the SCS (shutdown cooling system) line, branch piping of the RCS (reactor coolant system) line, shows that the CUF (cumulative usage factor) value exceeds 1.0, ASME Code limit, in case thermal stratification load is included. The HPSI (high pressure safety injection) line, re-branch piping, shows that temperature difference be-tween top and bottom of piping exceeds the criterion temperature, 28, and that the CUF value exceeds 1.0. Therefore, these branch pipings require a detailed review, monitoring or analysis. In particular, it is recommended that the HPSI piping should be shifted backward to decrease the influence of turbulent penetration intensity from the RCS piping.
Keywords: Thermal stratification; Thermal fatigue estimation; RCS branch line; FSI scheme serious deformation in piping, and support damage.
- 1. Introduction Especially, periodic thermal stratification is capable of As more experience is accumulated in the operation causing the thermal fatigue cracking of piping. [8-11]
of existing power plants, the long-term effects of In 1987 and 1988, thermal fatigue cracking and thermal hydraulic phenomena, unaccounted for in the leakage in several PWR (pressurized water reactor) original designs, are being observed. [1-5] One of plants resulted in the issuance of NRC Bulletin 88-08.
these effects is the thermal stratification phenomenon. [10] In 1995, leakage from a drain line in the TMI-1 Thermal stratification is flow that is stabilized with plant was attributed to the effects of turbulence pene-temperature layers due to the density difference be- tration into the nominally stagnant uninsulated line.
tween hot and cold water. [6, 7] This thermal stratifi- Similar thermal cycling incidents have continued to cation in piping is capable of causing bending stress, a occur in other plants, including Tihange-1 and Dam-pierre-1, among others. [12, 13] In 1997, leakage This paper was recommended for publication in revised form by Associate from an HPI (high pressure injection)/Makeup line at Editor Jae Young Lee Corresponding author. Tel.: +82 31 750 5651, Fax.: +82 31 750 5651 Oconee increased the awareness of the NRC (Nuclear E-mail address: jkyoon@kyungwon.ac.kr Regulatory Commission) that there were continued
© KSME & Springer 2008 occurrences of thermal fatigue in small-diameter RCS
RIV000051 Date Submitted: December 22, 2011 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 2219 (reactor coolant system)-attached piping. In early 1998, there were discussions between the nuclear industry and the NRC regarding the need for addi-tional volumetric examination of Class 1 high-pressure safety injection piping.
Several investigations have attempted to identify thermal fatigue mechanisms and to develop tools to assess piping susceptibility to thermal fatigue effects.
The thermal stratification, cycling, and stripping (TASCS) program identified several critical parame-ters and offered predictive tools to assist in assessing Fig. 1. Schematic diagram of the branch lines connected to fatigue loadings for thermal-structural analysis. [6] the RCS piping.
Other studies pursued experimental investigation into the thermal cycling phenomena based on scaled ex- piping has hot-leg HPSI (high pressure safety injec-periments [14-18] or full-scale plant operation. [19] tion) piping and the RDT (reactor drain tank) piping.
Most notably, it has been shown that a swirling, vorti- Nominal diameter of the HPSI piping is 0.076 m cal flow structure, as opposed to turbulence penetra- and nominal diameter of the RDT piping is 0.051 m.
tion, can be established in a dead-ended branch line due to the flow in the RCS line. [14, 17] 2.2 Estimation procedure In this study, thermal fatigue estimation due to thermal stratification in the RCS branch line of In this study, a one-way FSI scheme is applied to KSNPP (Korea Standard Nuclear Power Plant) is evaluate the thermal stratification piping. Fig. 2 performed using one-way FSI (fluid and structure shows this estimation procedure performed by using interaction) scheme. Detailed thermal loading due to the one-way FSI scheme. First, geometry and mesh thermal stratification and cycling is evaluated based for numerical analysis is generated. Next, thermal on temperature distributions with time, which is cal- flow analysis on thermal stratification piping is per-culated by the CFD analysis. Fatigue effects are con- formed by the CFD code. Temperature difference servatively estimated by a modified method that between top and bottom of piping is compared with combines ASME NB-3600 with NB-3200. Finally, the criterion temperature, 28(50) stated in refer-detailed inspection locations and mitigation schemes ence. [6, 10, 11] The only solid region except the for the integrity maintenance of piping are recom- fluid region out of the CFD results is transferred into mended. the stress analysis. At this time, geometry, mesh and temperature distribution data of solid region are con-
- 2. Estimation schemes verted into input data format for stress analysis by some users operation for MpCCI (mesh-based paral-2.1 Estimation model description lel code coupling interface) between CFD code and Schematic diagram for the SCS (shutdown cooling CSD (computational structure dynamics) code. A system) piping branched to RCS piping is shown in special MpCCI code was not used. Therefore, all wall Fig. 1. mesh and temperature distribution data with time The SCS of a nuclear power plant takes charge of were directly imported into the input data of stress continually removing heat when the reactor shutdown analysis model without any calculation for heat trans-occurs. All valves in the SCS piping are isolated dur- fer coefficients. This scheme is different from previ-ing normal or startup operating condition. Also, turbu- ous studies which use the average heat transfer coef-lent penetration in that the higher temperature coolant ficients of wall surface in stress analysis and it is out of the RCS piping penetrates into the SCS piping more realistic. Fatigue effects are estimated by a that is stagnant occurs. In Fig. 1, the RCS hot-leg that modified method that combines ASME NB-3600 the higher temperature coolant passes is piping with with NB-3200. This is to reflect the thermal stratifica-inner diameter of 1.07 m. The SCS piping concerned tion load to the existing design stress. Finally, detailed in this study is piping that the nominal diameter is monitoring locations and mitigation schemes for the 0.406 m and the schedule is 160. Also, the SCS integrity maintenance of piping are recommended.
RIV000051 Date Submitted: December 22, 2011 2220 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227
µ
( u j ) = µ + t x j x j x j (4)
+ C1 ( Pk + Gb ) C2 k
Stress equilibrium equation ij
+ bj = 0 (5) xi where, b j is external force.
Energy equation
µt k f T Fig. 2. Estimation procedure using one-way FSI scheme. x j
( u jT ) = +
x j t C p x j (6)
- 3. Numerical analysis where, the coefficient, source term, and turbulent constants are as follows:
3.1 Governing equations For the FSI evaluation, governing equations for µ t = Cµ k 2 /
thermal flow and structure are needed. In this study, u u u unsteady, incompressible and three-dimensional con- Pk = µt i + j i x
servation equations are used as governing equations j xi x j for the thermal flow analysis. Stress equilibrium µ T Gb = t g i equation is used for the stress analysis. Standard k- t xi model is used for turbulent model and Boussinesqs t = 0.85, k = 1.0, = 1.3, Cµ = 0.09 ,
approximation is used for the buoyancy effects. As- C1 = 1.44, C2 = 1.92 suming that all properties are constant under given temperature and pressure, the governing equations used are as follows: 3.2 Numerical schemes The FLUENT code [20] based on finite volume Continuity equation method is used for the CFD analysis. The ABAQUS code [21] based on the finite element method is used
( ui ) = 0 (1) for stress analysis. Finally, fatigue estimation is per-xi formed by the PIPSIS program. [22] The grid system Momentum Equation for CFD analysis is shown in Fig. 3. The number of cells is 87,776. The length from the connection point x j
( u jui ) = xp + gi (T Tcold ) of the RCS piping with the SCS piping to the outlet of i the RCS hot-leg is assumed to be more than 20 times (2) the SCS piping diameter to reflect on flow change in u u j 2
+ ( µ + µt ) i + k the connection part and to improve convergence. The x j ij x j xi 3 range of analysis for the SCS piping, for the HPSI piping, and for the RDT piping is set to the extent of Turbulent equation (standard k-) suitable length passing the 1st valve in consideration of thermal stratification effect and support position.
µ k (u j k ) = µ + t The SIMPLE (semi-implicit method for pressure x j x j k x j (3) linked equations) algorithm is used to calculate the
+ Pk + Gb pressure field at each cell. [23] Upwind scheme is
RIV000051 Date Submitted: December 22, 2011 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 2221 Fig. 3. Grid systems for the numerical analysis.
used to determine the convection term. The conver-gence criterion is that the residual is less than 1.0x10-5 at the each time step. To satisfy this convergence criterion, iterations of less than 50 times per time step Fig. 4. Experiment schematic for verification of numerical schemes.
of 1 second are needed. Unsteady CFD calculation is performed until 3000 second. To improve the conver-gence, under-relaxation factors are applied. Computer time for only CFD calculation took about 16 days using the Pentium 2.0 GHz.
In this study, thermal stripping of the temperature layer in the fluid region and two-way FSI scheme are ignored. To simulate the stripping, a high turbulent model like LES model is needed. However, this high turbulent model and two-way FSI method demand too much more time and the problem is difficult to solve actually.
3.3 Boundary conditions Fig. 5. The comparison of CFD results with experimental results.
Temperature and flow rate of coolant in inlet of the RCS hot-leg are 327 and 7718 kg/s, respec- 15.5 MPa are used for the properties of fluid. The tively. Inlet turbulent intensity is assumed to be 10 material of solid is assumed to be SUS304.
percent for hydraulic diameter. Outlet boundary con-dition is the constant pressure condition. All outer 3.4 Experimental verification surfaces of piping including the RCS piping are as-sumed to be adiabatic wall. All valves in the SCS To verify the numerical schemes used in this piping, the HPSI piping and the RDT piping are as- analysis, a simplified experiment with one branch sumed to be isolated. There is no leakage throughout line as shown in Fig. 4 was performed at small scale.
valve disks. The disk thickness in valves is assumed [18] Hot water temperature and flow rate of the main to be as two times as piping thickness. Each end sur- piping were 80 and 4.65 kg/s and cold water tem-face of branch piping in the range of analysis is as- perature was 20. CFD calculation for comparison sumed to be isolated and to be a low temperature with experimental results was performed with the wall of 49. In the process of numerical calculation, same schemes (the number of meshes, turbulent the initial temperature condition is set to be 49. model, algorithm and so on) mentioned in session The values for condition of average temperature in 3.2. Fig. 5 shows a comparison of the CFD result
RIV000051 Date Submitted: December 22, 2011 2222 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 with the experimental result. There is some differ- when the main flow in the RCS line creates a secon-ence in accuracy but the trend is similar. Therefore, dary flow in a branch line. Length of turbulent pene-numerical schemes adopted in this study are consid- tration in branch line depends on the velocity and ered to be suitable because the purpose of this esti- temperature of the RCS flow. This turbulent penetra-mation is to look for the detailed monitoring location tion mainly occurs during plant heat-up and cool-and mitigation scheme for the integrity maintenance down operations and becomes the source of thermal of piping, and because much mesh and high turbulent stratification. [6, 19, 24, 25] Fig. 6 shows the tem-model demand too much time and are capable of perature distribution at 100 sec. Turbulence penetrates generating unstable convergence. rapidly into the SCS piping from the RCS piping; therefore, a thermal stratification effect in the hori-
- 4. Results and discussions zontal piping of the HPSI line appears due to the tur-bulent penetration from the SCS piping. At the begin-4.1 Thermal flow analysis ning of penetration, the fast inflow from the RCS To evaluate the temperature distributions for the piping generates a higher temperature for the inner SCS, HPSI and RDT lines due to the turbulent pene- wall than the outer wall in the SCS piping.
tration, a transient 3-dimensional numerical thermal Fig. 7 shows the temperature distribution at 500 sec.
hydraulic analysis was performed by the CFD code, Thermal stratification phenomenon is shown in the FLUENT. horizontal part of the SCS piping. However, this ef-Fig. 6 to Fig. 7 shows the temperature distribu- fect in the HPSI piping was largely decreased despite tions with time in the SCS piping including the continuous penetration. This is judged to result from a HPSI piping and the RDT piping. Turbulence occurs strong thermal mixing effect as the piping diameter is (a) Inner wall (b) Outer wall (a) Inner wall (b) Outer wall (c) Detail contour in cross sectional area (c) Detail contour in cross sectional area Fig. 6. Temperature distributions with time in branch lines Fig. 7. Temperature distributions with time in branch lines (t=100 sec). (t=500 sec).
RIV000051 Date Submitted: December 22, 2011 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 2223 small. 19.4 is observed at 500 sec and the temperature Fig. 8 shows measurement positions for tempera- difference is decreased after 500 sec.
ture difference review. Nine positions were totally Fig. 11 represents the temperature difference investigated. changes between top and bottom inner wall at the Fig. 9 represents the temperature changes with time points 5, 6 and 7 with time. The points 5 to 7 are lo-at point 1 in the vertical piping of the SCS piping that cated in the horizontal part of the HPSI piping con-is near the RCS piping. Four points that were located nected with the SCS piping. As all points are directly at intervals of 90° in the cross-sectional area were affected by turbulent penetration from the SCS piping, examined. At the beginning of turbulent penetration a severe temperature difference is shown that exceeds from the RCS piping, each point has a different tem- the criterion temperature, 28.
perature due to the flow direction and the difference Fig. 12 represents the temperature difference of penetration intensity. However, the temperature changes between top and bottom inner wall at point 8 difference is rapidly decreased as time passes, and the with time. This point is located in the horizontal pip-temperature values at all points begin to be similar ing of the RDT piping connected with the SCS piping.
after 400 sec. A temperature difference appears but is tiny. It is Fig. 10 shows the temperature difference changes judged that this result is because the drain piping is between top and bottom inner wall at point 3 with located backward compared with the HPSI piping and time. Point 3 is located at the starting point of the the magnitude of turbulent penetration from the SCS horizontal piping passing the 1st elbow of the SCS piping is only slight.
piping. The maximum temperature difference of 40 Shutdown Cooling Line 30 O
28 C 20 T [ C ]
o point 3 10 0
0 500 1000 1500 2000 2500 3000 Time [sec]
Fig. 10. Temperature changes with time at point 3.
Fig. 8. Schematic diagram of the positions for temperature measurement.
80 340 Hot Leg Injection Line 60 point 5 320 point 6 Temperature [ C ]
o point 7 Shutdown Cooling Line T [ C ]
40 o
O 300 20 28 C point 1(I) point 1(II) point 1(III) point 1(IV) 0 280 0 200 400 600 800 1000 0 200 400 600 800 1000 Time [sec] Time [sec]
Fig. 9. Temperature changes with time at point 1. Fig. 11. Temperature changes with time at points 5, 6 and 7.
RIV000051 Date Submitted: December 22, 2011 2224 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 10 Table 1. Thermal stratification stress intensities.
Reactor Drain Tank Line 8 No. of ST/S Line Location point 8 Node (MPa) 6 5 Weldment of Nozzle 401.7 30 90 Elbow 370.7 T [ C ]
Shutdown o
4 40 Tee Junction 394.8 Cooling 2 60 Tee Junction 82.7 65 Weldment of Valve 118.5 0
330 90 Elbow 89.6 0 500 1000 1500 2000 2500 3000 Hot Leg 346 Support 39.3 Time [sec] Safety Injection 350 90 Elbow 21.4 Fig. 12. Temperature changes with time at point 8. 355 Weldment of Valve 14.5 4.2 Stress/fatigue analysis Table 2. Cumulated usage factors (CUF).
All wall temperature distribution and mesh data No. of Design S*P Revised Line with time were directly imported into the input data of Node CUF (MPa) CUF stress analysis model without any calculation for heat 5 0.337 1166.5 0.461 transfer coefficients. Thermal stress loads due to the 30 0.488 1156.1 0.631 turbulent penetration were analyzed by the FEM code, Shutdown 40 0.818 2744.3 1.229 Cooling ABAQUS. 60 0.719 2818.0 1.000 For each node location as shown in Fig. 1, thermal 65 0.228 842.0 0.228 stratification stress intensity, ST/S, is indicated in Table 330 0.155 737.2 0.155
- 1. As only thermal load was considered, therefore, Hot Leg 346 0.097 785.5 0.099 pressure and moment loads should be included in the Safety 350 0.153 769.6 0.153 peak stress to evaluate the fatigue effects of each line. Injection To include thermal stratification stress intensity, a 355 <0.001 223.2 <0.001 modified peak stress intensity range, Sp*, was calcu-lated as follows: at other locations was insignificant to maintain the fatigue integrity.
Sp* = Sp + ST/S (7) 4.3 Recommendations where, Sp is a design peak stress intensity that is cal-culated by Eq. 11 of ASME Section III, NB-3653.2, In branch layout lines that the CUF is shown highly and ST/S is a thermal stratification stress intensity that in this study, it is recommended that for these parts is calculated by NB-3215. for a fully detailed stress analysis should be per-Using the PIPSYS program, which is the piping formed or should be managed in the minimum using design program of KSNPP, alternating stress intensity, enhanced inspection or monitoring for possible fa-Salt, was calculated by NB-3653.3 or NB-3653.6 and tigue failure or leakage.
the cumulative usage factors (CUF) were evaluated In particular, a scheme to mitigate the thermal by NB-3653.4 and NB-3653.5. stratification effect in the HPSI piping should be con-For each node location as shown in Fig. 1, design sidered. Fig. 13 is a schematic diagram suggested to CUF and revised CUF are summarized in Table 2. mitigate the thermal stratification effect in the HPSI The CUF of node 40, where a tee junction is con- piping. To minimize the calculation time, the layout nected between the SCS piping and HPSI piping, was of the SCS and the HPSI lines was simplified and the increased suddenly because of thermal stratification RDT line was excluded. Fig. 14 shows temperature in the HPSI piping due to the secondary turbulent difference in the HPSI piping compared to the case penetration. Also, the CUF of node 60, where a tee connected to vertical piping of the SCS line with junction is connected between the SCS piping and the case connected to horizontal piping of the SCS RDT piping, was increased. The increase of the CUF line. Temperature difference of the case connected
RIV000051 Date Submitted: December 22, 2011 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 2225
- 5. Conclusions A thermal fatigue estimation scheme for a ther-mally stratified branch line that has re-branch line was developed. Generally, the thermal stratification effect of re-branched lines has not been considered in the fatigue evaluation for plant design. In this study, a one-way FSI scheme is used to evaluate the thermal stratification piping. Thermal flow analysis, stress analysis and fatigue estimation were performed in (a) Case connected to the vertical piping serial order. Finally, detailed monitoring locations and mitigation scheme for the integrity maintenance of piping were recommended. All wall mesh and transient temperature distribution data obtained in the CFD analysis were directly imported into the input data of stress analysis model without any calculation for heat transfer coefficients. This scheme is different from the previous studies which have used the aver-age heat transfer coefficients of wall surface in stress analysis and is more realistic.
The CUF, cumulated usage factors, for fatigue ef-fect review with node were calculated. A modified method that combines ASME NB-3600 with NB-3200 was used. This is because the previous estima-(b) Case connected to the horizontal piping tion method uses just the ASME Section III, NB-3600 Fig. 13. Schematic diagram suggested to mitigate the thermal that cannot consider the thermal stratification stress stratification effect of HPSI line.
intensity. Thermal stratification stress intensity is 80 obtained from ASME Section III, NB-3200. Modified mid-vertical peak stress includes thermal stratification stress inten-mid-horizontal sity to design peak stress intensity obtained from 60 ASME Section III, NB-3600.
In this study, the SCS line, branch piping of the 40 RCS line, shows that the CUF value exceeds 1.0, T [K]
ASME Code limit, in case thermal stratification load 20 is included. The HPSI line, re-branch piping, shows that the temperature difference between top and bot-0 tom of piping exceeds the criterion temperature, 28
-200 0 200 400 600 800 1000 1200 1400 and that the CUF value exceeds 1.0. Therefore, on Time [sec] these branch lines, a detailed review, monitoring or Fig. 14. Temperature difference change in the HPSI piping analysis is required. In particular, it is recommended compared the case connected to vertical piping of SCS line that the HPSI piping should be shifted backward to with the case connected to horizontal piping of SCS line. decrease the influence of turbulent penetration inten-sity from the RCS piping.
to horizontal piping is lower than that of the case Thermal stripping and two-way FSI method were connected to vertical piping. Thus, it is recommended ignored in this study, but these can be possible if an that HPSI piping should be shifted backward to de- economical high turbulence model and rapid com-crease the influence of turbulent penetration intensity puter is developed. Therefore, further study on these from the RCS piping. is required.
RIV000051 Date Submitted: December 22, 2011 2226 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 perimental Studies of a Stratified Flow in a Pipe, References NURETH-6 Conference, France, October 5-8, I,
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[8] EPRI, Operating Experience Regarding Thermal Fatigue of Unisolable Piping Connected to PWR Reactor Coolant Systems (MPR-25), TR-1001006, (2000). Kwang-Chu Kim received his
[9] NRC, Cracking in Feedwater System Piping, Bulle- B.S. , M.S. and Ph.D degrees tin No. 79-13, (1979). from department of mechanical
[10] NRC, Thermal Stresses in Piping Connected to engineering, Kyunghee Univer-Reactor Coolant Systems, Bulletin 88-08, (1988). sity in 1993, 1995 and 2000,
[11] NRC, Pressurizer Surge Line Thermal Stratifica- respectively. He has worked for tion, Bulletin No. 88-11, (1988). Korea Power Engineering Com-
[12] OECD NEA, Thermal Cycling in LWR compo- pany since 1995 and he is now a nents in OECD-NEA member countries, (2005). senior researcher. Dr. Kims research area includes
[13] R. Magee, et al., J. M. Farley Unit 2 Engineering CFD analysis, flow control, plant design and simula-Evaluation of the Weld Joint Crack in the 6" tor.
SI/RHR piping, WCAP-11789, (1988).
[14] M. Robert, Corkscrew Flow Pattern in Piping Jong-Han Lim received his System Dead Legs, NURETH-5 Conferenc, (1992). B.S. degree from department of
[15] N. Nakamori, K. Hanzawa, T. Ueno, J. Kasahara, mechanical engineering, Cho-and S. Shirahama, Research on Thermal Stratifica- sun University in 1981, M.S.
tion in Un-isolable Piping of Reactor Coolant Pres- and Ph.D degrees from depart-sure Boundary, Experience with Thermal Fatigue ment of mechanical engineering, in LWR Piping Caused by Mixing and Stratification, Kyunghee University in 1986 Specialist Meeting Proceedings, (1998). and 1992, respectively. He
[16] R. M. Roidt and J. H. Kim, Analytical and Ex- worked for Hyundai Motors Company during 1986-
RIV000051 Date Submitted: December 22, 2011 K.-C. Kim et al. / Journal of Mechanical Science and Technology 22 (2008) 2218~2227 2227
- 95. He is now a professor in department of mechani-cal & automotive engineering, Kyungwon University.
Dr. Lims research interests are in the area of thermal flow, internal combustion and liquid atomization.
Jun-Kyu Yoon received his B.S. degree from department of mechanical engineering, Cho-sun University in 1981, M.S.
degree from department of me-chanical engineering, Kyung-hee University in 1987 and Ph.D degree from department of mechanical engineering, Myongji University in 2001. He worked for Hyundai Motors Company and Asia Motors Company during 1985-96. He is now a professor in department of mechanical & automotive engineering, Kyungwon University. Dr. Yoons re-search interests are in the area of flow control, heat transfer, liquid atomization, spray and combustion.