For the following an ideal reheat-regenerative Rankine cycle with one reheater and two open
feedwater heaters. if y= 0.24 and z=0.04 find
the specific turbine work
Boiler
High-P
turbine
Reheater
Low-P
turbinc
1-y-2
(10)
(11 12
Open
FWH
11
Open
FWH
Condenser
P III
(
PI1
PI
12
11
10
91
8
6
5
4
3
2540 3151 3610289030403630868.5858.5455452192 .2191
2
ادارات​

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

What is creep? what is stress relaxation?

Consider airflow over a flat plate of length l = 1.5 m under conditions for which transition occurs at le = 0.9 m based on the critical reynolds number, re,e = 5 x 10. evaluating the thermophysical properties of air at 400 k, determine the air velocity. (hint: use the tables to find the properties of air)