ldibut2003
26.11.2019 •
Physics
In large buildings, hot water in a water tank is circulated through a loop so that the user doesn’t have to wait for all the water in long piping to drain before hot water starts coming out. a certain recirculating loop involves 40-m-long, 1.2-cm-diameter cast iron pipes with six 90° threaded smooth bends and two fully open gate valves. if the average flow velocity through the loop is 2 m/s, determine the required power input for the recirculating pump. take the average water temperature to be 60°c and the efficiency of the pump to be 76 percent. the density and dynamic viscosity of water at 60°c are rho = 983.3 kg/m3, μ = 0.467 × 10–3 kg/m·s. the roughness of cast iron pipes is 0.00026 m. the loss coefficient is kl = 0.9 for a threaded 90° smooth bend and kl = 0.2 for a fully open gate valve. (round the final answer to three decimal paces.)
Solved
Show answers
More tips
- S Science and Technology How to Restore the Diamond Shine to Your Tarnished Silverware...
- C Computers and Internet Boost your processor performance with these easy tips...
- L Leisure and Entertainment When will Maslenitsa start?...
- F Food and Cooking Discovering the Mysterious Fruit of Feijoa...
- B Business and Finance How to Open an Online Store? A Detailed Guide for Beginners...
- W Work and Career How to Write a Resume That Catches the Employer s Attention?...
- C Computers and Internet Е-head: How it Simplifies Life for Users?...
- F Family and Home How to Choose the Best Diapers for Your Baby?...
- F Family and Home Parquet or laminate, which is better?...
- L Leisure and Entertainment How to Properly Wind Fishing Line onto a Reel?...
Answers on questions: Physics
- M Mathematics Your bedroom measures 3 1/2 yards by 4 1/4 yards if you wanted to carpet the bedroom, and you were able to buy a carpet measuring 5 yards by 5 yards, how many square yards...
- W World Languages What sub sandwich place : blimpie quizno jimmy johns schlotzskys jersey mikes subway firehouse potbelly...
- H Health a shopkeeper bought two radios for rs 6000 he sold one of them at a profit of 20% and other at a loss of 10% if he gained 2% on his total outlay at what price did he buy each...
- C Chemistry Sort the length measurements in increasing order of magnitude from smallest to largest Drag each tile to the correct box Tiles Sequence micrometer Kilometer decimeter centimeter...
- H History Como os trabalhadores descrevem a si mesmo no texto?...
Ответ:
The power input is 0.102 kW
Solution:
As per the question:
Length of the loop, L = 40 m
Diameter of the loop, d = 1.2 cm
Velocity, v = 2 m/s
Loss coefficient of the threaded bends,
Loss coefficient of the valve,
Dynamic viscosity of water,
Density of water,
Roughness of the pipe of cast iron,
Efficiency of the pump,
Now,
We calculate the volume flow rate as:
where
= Volume rate flow
A = Area
v = velocity
For this, Reynold's N. is given by:
Since, > 4000, the flow is turbulent in nature.
Now,
With the help of the Colebrook eqn, we calculate the friction factor as:
f = 0.05075
Now,
To calculate the total head loss:
Now,
The drop in the pressure can be calculated as:
Now,
to calculate the input power:
Ответ:
explanation:
hdshusjshssh