Design of a Reaction Steam Turbine

111 Pages·02.101 MB·English

by  Qayyum, Abdul

DESIGN
OP
A REACTION STEAK TURBINE
THESIS
Submitted in Partial Fulfilment
of the requirements for the
degree of
MASTER OF MECHANICAL ENGINEERING
at the
POLYTECHNIC INSTITUTE OF BROOKLYN
by
Abdul Qayyum
Sept.1950
Approved:
esis Adviaer
Head of Den^tment
ProQuest Number: 27591624
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V I T A
The autnor was born in Kotli Loharan, West Punjab, Pakistan
on Dec^nber 15th,1926.
He went to school in Nairobi, Kenya Colony, British Bast
Africa, completing the London Matriculation deamination in July, 1942
and the Senior Cambridge in December of the same year*
He joined the University of Punjab at Lahore (Pakistan)
in 1943 and took his B.A. degree in June,1946.
The academic year of 1946-47 was spent in graduate work
in Physics at the Muslim University of Aligarh,U.P.(India).
In August 1947f to pursue higher technical learning,the
author travelled to the United States and entered the University
of Utah, Salt Lake City completing the requirements for B.S.M.E.
in June, 1949. Since then he has been in the Polytechnic Institute
of Brooklyn and this present thesis represents, in part, his
efforts towards Master *s Degree in Mechanical Engineering at the
Polytechnic Institute of Brooklyn.
( i )
AGKNGfLEDGMMT
The author expresses his sincerest appreciation to
Professor Edwin F. Church Jr. for his advice and encouragement
throughout the study and regards it with great pride to have
worked under his distinguished guidance but for which the pro­
gress of the thesis would have been greatly impeded.
( Ü )
ABSTRACT
The design of the 7500 kw ( net Output ) Reaction Turbine
the first stage being a two-row velocity stage, was undertaken in
parallel with an equivalent Impulse Turbine, which was designed in
the course ” Steam Turbines” at Polytechnic Institute of Brooklyn,
given by Professor Edwin F. Church in Fall 1949.
This parallel study revealed that whereas ninteen stages
were necessary for the Impulse Turbine, the Reaction Turbine, be­
cause of comparatively lesser enthalpy drop per stage , required
twenty-four individual stages under similiar conditions. This to­
gether with the apurent higher stage efficiency of the Reaction
Turbine resulted in a higher over-all turbine efficiency or engine
efficiency. In consequence a less volume of steam under the same
conditions was required thus resu Iting in a more economic opera­
tion of the Reaction Turbine, and hence justifying the initial
greater cost of the Reaction Turbine because of its more numerous
stages. To summarize then Reaction Turbine offers an apparently
distinct advantage over the Impulse Turbine.
Ahmed, Mukhtar , thesis M lo43 , 1950, Spicer Library, Polytechnic
Institute of Brooklyn.
( iii )
TABLE OF CONTENTS
I . AGKNCMLEDGEHjENTS .......................... ii
II . ABSTRACT .................................... iii
in . SYMBOLS ............... vii
IV . REACTION TURBINE.............................. 1
V . OBSERVATIONS......................... 5
VI . PROCEDURE IN DESIGN OF REACTION TURBINE......... S
VH ♦ SAMPLE CALCULATIONS OF INDIVIDUAL STAGES......... 14
VIII # APPENDIX ................................... 92
IX . BIBLIOGRAPHY................................. 100
( iv )
TABLE OF FIGURES AND GRAPHS
Page
I . Velocity Diagram , Stage Z .................... 15
II . Velocity Diagram, Stage Y ...... 19
III . Velocity Diagram , Stage X .................. 23
IV . Velocity Diagram , TwoGrow velocity Stage ...... 27
V . Velocity Diagram , Stage 2.,................... 34
VI . Velocity Diagram , Stage 3 ...................... 36
VII * Rotor Skeleton ........ ......................
¥111 • Velocity Diagram, Stage 4 • • 40
IX . Velocity Diagram, Stage 5 ...................... 42
X ..Velocity Diagram, Stage 6 ...... 44
XI . Velocity Diagram, Stage 7 ............... 47
XII . Velocity Diagram, Stage 8 ...... 49
XIII . Velocity Diagram, Stage 9 .......... 52
XIV . Velocity Diagram, Stage 10..................... 54
XV ..Velocity Diagram, Stage 11 ..................... 56
XVI . Velocity Diagram, Stage 12 ............ 59
XVII . Velocity Diagram, Stage 13 ..... 6l
XVIII . Velocity Diagram, Stage 14.......... 63
XIX . Velocity Diagram, Stage 15................... 65
XX . Velocity Diagram, Stage 16 ................... 68
XXI . Velocity Diagram, Stage 17 .................. 70
XXII . Velocity Diagram, Stage 18................ 72
XXIII . Velocity Diagram, Stage 19..................... 75
( V )
TABLE OF FIGURES AND GRAPHS
Page
XXIV ♦ Velocity Diagram, Stage2 0 ........ 77
XXV # Velocity Diagram, Stage2 1 .............. 80
XXVI . Velocity Diagram, Stage2 2 .............. 83
XXVII . Ehergy Distribution , Table No.l............. 84
XXVIII . Velocity Diagrams data. Table No.2 .............. 88
XXIX • Internal Work Done and Stage Efficiencies,
Table No. 3 ..... 89
XXX . Rotor Profile...... 90
XXXI . Reheat Factor for Infinite Stages ........ 93
XXXII . Cumulative Energy Diagram ....................... 94
xXXIII . Comparison of Values of Nozzle and Blading
Efficiencies, Table No. 4 .................. 95
XXXIV. • Comparison of Stage Efficiencies, Table No.5..,,* 96
XXXV . Reaction Blading Leakage.............. 97
XXXVI • Nozzle Blading Efficiencies, Table Mo.6 ......... 98
XXXVII « Nozzle and Blading Efficiency Graph ...... 99
( vi )
LIST OF SYMBOLS
A = area, square feet or square inches,
d » diameter , ft.
e * internal work done in the stage.
= internal work done by a turbine as a \diole per pound of steam.
E a energy or work per pound of steam , Btu ot foot-pounds
according to context.
h * enthalpy per pound of steam.
( ^ h)^ - ideal available energy per pound of steam.
% - isentropic enthalpy drop in moving blades*
Hg = isentropic enthalpy drop in fixed blades.
J = mechanical equivalent of heat « 778
=■ velocity coefficient for flow through a nozzle.
kb = velocity coefficient for flow through blade passages.
m » thickness coefficient for blade or nozzle edges.
p - pressure, pounds per square inch absolute, unless otherwise
stated.
= reheat, Btu per pound,
r = per cent reaction.
R = reheat factor.
T,t = temperature degrees Farenheit.
V = velocity feet per second.
Vb • velocity at mean blade ring diameter.
V2 - absolute velocity at entrance.
^2r “ relative velocity at entrance.
( vii )
Symbols - Contd.
^3r* relative velocity at exit.
V3 =• absolute velocity at exit.
V » absolute exit velocity of the previous stage.
3v
V = specific volume, cubic feet per pound,
w = actual weight flow, pounds per second.
X » percentage dryness or quality of steam.
Greek Letters:
oc - angle made by steam velocity^ ) with direction of blade
velocity.
P = blade entrance angle.
X = blade exit angle.
S = angle made by absolute exit velocity.
« difference or increment,
nozzle efficiency.
(1^^= blading efficiency,
ft = nozzle and blading efficiency,
stage efficiency,
mgine efficiency,
f/ = carry-over coefficient.
^a>
0 = percentage of circumference occupied by active nozzles.
1^ = ratio of blade speed to steam speed.
^ - entropy.
Subscripts;
1 - initial conditions.
2 « intermediate conditions.
3 * final conditions.
( viii )