THERMAL. PERFORMANCE OF A WATER BODY DUE TO HEATED WATER DISCHARGE FROM
THE POWER PLANTS
by
L. D PAPNEY
Thesis submitted
in fulfillment of the requirements for the award of the degree of
DOCTOR OF PHILOSOPHY
Department of Mechanical Engineering
INDIAN INSTITUTE OF TECHNOLOGY, DELHI
Hauz Khas, New Delhi-110 016 December, 1996
DEDICATED TO MY PARENTS
CERTIFICATE
This is to certify that the thesis entitled," Thermal Performance of a Water Body due to Heated Water Discharge from the Power Plants," being submitted by Mr. L. D. PAPNEY to the Indian Institute of Technology, Delhi, for the award of the degree of "Doctor of Philosophy" is a bonafide record of the candidate's own research work carried out by him under my guidance and supervision. In my opinion, the thesis has reached the standard fulfilling the requirements of all the regulations relating to the degree.
The results contained in this thesis have not been submitted, in part or full, to this Institute or any other University or Institute for the award of any degree or diploma.
Dr. S. K. GUPTA Associate Professor
Mechanical Engg. Department Indian Instt. of Technology New Delhi.
ACKNOWLEDGEMENTS
I express my deep sense of gratitude and sincere thanks to Dr. S. K. Gupta for his highly encouraging and inspiring guidance throughout this work. The interest shown by him together with his unfailing patience and indefatigability have been a constant source of inspiration to me and has enabled me to bring this work to a successful completion which may not otherwise have been possible.
I am indebted to the Environmental Division of NTPC, N. Delhi for furnishing me the site data of Singrauli area for use in this study. I thank the UPSEB authorities at Anpara Super Thermal Power Station and NTPC authorities at Singrauli Super Thermal Power Station for their kind help and cooperation in furnishing me the plant operation data and requisite information on Rihand reservoir. The support extended by Dr. V. K. Sethi of CEA while at Anpara site is also acknowledged.
I wish to express my sincere thanks to my superiors and colleagues in the Central Electricity Authority (CEA), N. Delhi, for their constant support and inspiration. I am .specially grateful to S/Shri S. Seth Vedantham, K. S. Chaube, R. K. Soni, N. K. Nair, and J. Jha for their help, guidance and encouragement to complete this work.
I acknowledge the stimulating discussions held with Shri R. Sundar Rajan of NTPC, NOIDA, and Shri Ajit Gupta of ABB, N. Delhi (formerly in NTPC, NOWA).
Finally, I must mention that I owe a lot to my wife for bearing with me all the hardships during the entire period of this work at I.I.T., Delhi.
(L. I). PAPNEY)
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ABSTRACT
In this work, suitable mathematical models have been considered for predicting the thermal performance of a large water body.
The vertical temperature stratification in Rihand reservoir has been analysed by horizontally averaged one-dimensional model using turbulent eddy diffusion approach.
The variations in the water surface level of the reservoir due to various inflows and outflows have been taken into account. The energy associated with various inflows &
outflows, thermal discharge from the power plants, and solar radiation etc. have been considered. A computer software has been prepared for solving the model.
The model has been validated by comparing the results with the field data obtained from National Thermal Power Corporation (NTPC) Ltd., India. This field study was carried out by Messrs Electricite de France (EDF) International and Group Carbonnages de France (GCF) for NTPC during the years 1989 & 1990. The comparison between the predicted temperature profiles and the field data is quite good. The calibration coefficients have been estimated and sensitivity analysis has been carried out. Using these values of the coefficients, the periodic variations in temperature at different depths of the reservoir have been obtained. The effects of varying thermal discharge on the temperature profiles of Rihand reservoir have been studied. It is seen that for every 10000 MW of thermal load which is discharged into the reservoir, the average temperature of the reservoir rises by about 1.0°C.
ill
A vertically integrated two-dimensional surface layer model has been prepared for predicting the streamlines and temperature distribution near the intake and discharge points of a thermal power plant. The computer softwares have been prepared to solve these equations and obtain the streamlines and isotherms in the flow region. The model has been applied to study the effect of heated water discharge from Anpara Super Thermal Power Station into Rihand reservoir. It is seen that for a thermal discharge of 4332 MW at a characteristic flow velocity of 0.077 m/s and temperature rise of 9°C, the normal distance of 1 °C isotherm from the intake is about 4.0 km.
It is seen that the lake currents affect the streamlines pattern and temperature profiles in a significant way. Therefore, the effects of the lake currents must be considered while locating the intake and discharge points.
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CONTENTS
Page No.
CERTIFICATE (i)
ACKNOWLEDGEMENTS (ii)
ABSTRACT (iii)
CONTENTS (v)
LIST OF FIGURES (vii)
LIST OF TABLES (xi)
LIST OF APPENDICES (xii)
NOMENCLATURE (xiii)
CHAPTER 1 INTRODUCTION
CHAPTER 2 LITERATURE REVIEW 6
2.1 Vertical temperature stratification
2.2 Heated water discharge in a water body 12 CHAPTER 3 MATHEMATICAL MODELING FOR VERTICAL
TEMPERATURE STRATIFICATION 19
3.1 Introduction 19
3.2 Mathematical model 21
3.3 Model application 28
3.3.1 Input data 28
3.3.2 Solution procedure 31
3.3.3 Results and discussions 32
CHAPTER 4 TWO AND THREE DIMENSIONAL MATHEMATICAL
MODELS 39
4.1 Introduction 39
4.2 Mathematical model 41
4.3 Model application 50
4.3.1 Input data 50
4.3.2 Solution procedure 53
4.3.3 Results and discussions 54
CHAPTER 5 CONCLUSIONS 59
REFERENCES AND BIBLIOGRAPHY 63
FIGURES 75
APPENDICES 118
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