Question

1. (30points) Theoretical Questions a. Write general form of conservation of energy equation for an open system and explain each ter (5 points) b. Write general form of conservation of momentum equation for an open system and explain each term (5points) c. How do we define "flow work" and why is it important? (Spoints)

Answer 1

a-conservation of energy equation

Let mi and me be the masses entering and leaving the C.V. respectively. et let me and my be the manes iu C.v.initialt aud final conditions resp. unden cmservation of mass ilinlet) am mi-me (delor mi # exit(e), me Conservation of energy dE Ė; - É dt de dei _dee Peter dt It dt Energy at ulet, E; = mihi + į mic? + migz; +Q hitta Energy at out let . Eea mehe te me cê tmegzethet Ide d (mini tf micfumigzi+Q) - de (mehe ty mecz + meyzet W) Idt CV

Here mc²+mg2) is a part of internal (mh + 1 mc energy of the fluid - Q heat given to opensys. hy enthalpy mt mags I me? kinetic energy Wa work done by open system 2 mg2+ potential energy. conservation of momentum equatim - su D=d au ox -luovute D²u I optf at 72=22 дҳ г. where du change in velocity with time dt CAcceleration term)

tlv.ua Advectim term - force exerted on a particle of fluid by the other particles of fluid Surrounding it. vo?l >[Viscosity Constant controlled ] Velocity diffusion term - (this term descojbles b how fluid motim is damped) ( Highly viscous fluids stick together choney)] [ low - viscosity fluids flow freely air)] .1 OP → pressure term - fluid flows in the direction of 3 largest change in pressure. if + Body force term External forces that act on the fluid (such as gravity etc.)
c-
* flow work The wolk teansfer in causing the fluid to leave the element either to enter or control volume is Kia How work. dA dm dA foot A 2 dv=dAxa EP dA flow work = force x distance flowo work = pd Axx flow work = Pdv flow work Pov dom mars flow work Pre maus cl assume that mass is entering the cou, flow works prexm V - V :-) Varm flow work = P.V NOTE :- It thee feed enters at I then the entry flow work is -PV. with If the fluids leaves at 2. then the exist flow work is + Pz Vz, * It is important, because of this flow work flow continuous through a control volume.

pa solid V at Triple Ptp Supercaitical fluid phase critical coitical point Triple point and at Port pressure liquid Critical point phase gaseous point phase liquid -vapour combination vapour can exist in. (aitical Temp. Ttp To T [PT diagram for water] Critical point a point when liquid phase and vapoure phase becoming similar or exists both simultaneously of latent heat o is zero known as critical point. Triple point A at point or at which all three phases (gas liquid, salid) of that substance coverist in thermodynamic equillibrium Known as Triple point. 1

Buoyant force +(FB) Buoyant force is an upward force exested by a fluid that opposes the weight of a partially as fully immersed object. Its value is equal to the weight of the fluid displaced by the object and acted from the center of gravity of the displaced volume. example 프 of weight (mg), volume de Block FB = weight of the displaced liquid. VG 8 FB > FB= (mg) displaced liquid =)) Fo=8xvolume xg * it object år partially immersed then depth is up to a in liquid. FA so volume -(@AB) b Of displace liquid FB = ex (XAB) xЯ I C KA 오