Plate & Frame Heat Exchanger (PFHX)

of 2 /2
Plate & Frame Heat Exchanger (PFHX) Dr. Md. Zahurul Haq Professor Department of Mechanical Engineering Bangladesh University of Engineering & Technology (BUET) Dhaka-1000, Bangladesh http://zahurul.buet.ac.bd/ ME 307: Heat Transfer Equipment Design http://zahurul.buet.ac.bd/ME307/ © Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 1/7 Plate & Frame Heat Exchanger (PFHX) Plate & Frame Heat Exchanger (PFHX) T1032 T1031 © Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 2/7 Plate & Frame Heat Exchanger (PFHX) T1033 © Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 3/7 Plate & Frame Heat Exchanger (PFHX) T765 T766 NTU = U o A o N s (mC p ) min , A o = bl Effective NTU = F corr NTU , F corr = 1 - 0.0166NTU Heat transfer & pressure loss correlations are based on the hydraulic diameter, D h of the passage formed by the two plates. © Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 4/7

Transcript of Plate & Frame Heat Exchanger (PFHX)

Page 1: Plate & Frame Heat Exchanger (PFHX)

Plate & Frame Heat Exchanger (PFHX)

Dr. Md. Zahurul Haq

ProfessorDepartment of Mechanical Engineering

Bangladesh University of Engineering & Technology (BUET)Dhaka-1000, Bangladesh

http://zahurul.buet.ac.bd/

ME 307: Heat Transfer Equipment Design

http://zahurul.buet.ac.bd/ME307/

© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 1 / 7

Plate & Frame Heat Exchanger (PFHX)

Plate & Frame Heat Exchanger (PFHX)

T1032 T1031

© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 2 / 7

Plate & Frame Heat Exchanger (PFHX)

T1033

© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 3 / 7

Plate & Frame Heat Exchanger (PFHX)

T765 T766

• NTU = UoAoNs

( ˙mCp)min, Ao = bl

• Effective NTU = FcorrNTU , Fcorr = 1 − 0.0166NTU

• Heat transfer & pressure loss correlations are based on the hydraulic

diameter, Dh of the passage formed by the two plates.© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 4 / 7

Page 2: Plate & Frame Heat Exchanger (PFHX)

Plate & Frame Heat Exchanger (PFHX)

T767

•1Uo

= 1hh

+ 1hc

+∆Xp

k+ Rdi + Rdo

• Flow velocity, V =

{

2 ˙mρsb(Ns+1) : odd number of plates2 ˙m

ρsbNs, 2 ˙m

ρsb(Ns+2) : even number of plates

• Dh =4(cross−sectional area)

wetted perimeter= 4sb

2s+2b ≃4sb2b = 2s, Re = VDh

ν

• Laminar flow: Nu = 1.86(Gz)1/3(

µb

µw

)0.14; Gz = RePr

L/DRe < 100

• Turbulent flow: Nu = 0.374Re0.668Pr1/3; Re > 100

• Friction factor, f =

280Re

: 1 < Re < 10100

Re0.589 : 10 < Re < 10012

Re0.183 : Re > 100

• Pressure drop, ∆P = fLDh

(12ρV

2) + 1.3(12ρV

2p ) ≃

fLDh

(12ρV

2)

© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 5 / 7

Plate & Frame Heat Exchanger (PFHX)

• Flexibility of design through a variety of plate sizes and pass

arrangements

• Easily accessible heat transfer area, permitting changes in

configuration to suit changes in processes requirements through

changes in the number of plates

• Efficient heat transfer; high heat transfer coefficients for both fluids

because of turbulence and a small hydraulic diameter

• Very compact, and low in weight; in spite of their compactness,

1500 m2 of surface area is available in a single unit

• Only the plate edges are exposed to the atmosphere; the heat losses

are negligible and no insulation is required

© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 6 / 7

Plate & Frame Heat Exchanger (PFHX)

PFHX Rating ⊲ 0.975 kg/s water at 25oC is to be cooled using 1.0 kg/s water

available at 7oC. If b = 457 mm, L = 914 mm, s = 5.08 mm, t = 1.016 mm, k =

14.3 W/mK, Ns = 11, fouling coefficients for both fluids = 3.52 x 10−6, rate the

heat-exchanger.

© Dr. Md. Zahurul Haq (BUET) Plate & Frame Heat Exchanger (PFHX) ME 307 (2020) 7 / 7