1. More Non-Dimensional Models for Simple Heat Exchangers
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
Different Shape Functions for Compact Sobolev Devices …..

2. e-NTU Models for Simple Counter Flow HXs

3. e-NTU Models for Simple Parallel Flow Heat Ex
Thi
The
Tce
Tci

4. e- NTU Curves: Counter Vs parallel flow

5. Limiting Cases Two limiting cases of interest: R = 1 and R =0
For R = 1 above equation is indeterminate.
Apply L’ Hospital’s Rule .

6. L’ Hospital’s Rule Consider a function:
If there exist a real value c such that
has a finite value, then If

7. Two limiting cases of interest: R = 1
Counter flow Heat exchanger:
Parallel flow Heat exchanger:

8. HX with Equal Capacity Fluids

9. Condensing/Evaporative HXs
The limiting case of interest: R = 0.
Counter flow Heat exchanger:
Parallel flow Heat exchanger:

10. Condensing/Evaporative HXs
NTU

11. General Models for Simple Heat Exchangers

12. System of Equations

13. Non-dimensional Model - II
Counter Flow:
Parallel Flow:

14. Generalized Performance Charts for HX.

15. More Mathematics for Industrial Design
A single pass counter flow heat exchanger, with Cc<Ch.
Thermal Capacity Ratio:
Temperature Effectiveness:

19. A single pass counter flow heat exchanger, with Cc<Ch.

21. Design for Safety of A HXdi do Di