Jump to content



Featured Articles

Check out the latest featured articles.

File Library

Check out the latest downloads available in the File Library.

New Article

Product Viscosity vs. Shear

Featured File

Vertical Tank Selection

New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

2
- - - - -

Rising Film Evaporator

heat transfer evaporation boiling

8 replies to this topic
Share this topic:
| More

#1 lanco

lanco

    Brand New Member

  • Members
  • 4 posts

Posted 23 June 2025 - 02:24 PM

Hi,

 

I have to design a rising film evaporator for an organic solution.

 

Could someone recommend a literature source to calculate heat transfer coefficient inside tubes?

 

Thanks in advance.



#2 breizh

breizh

    Gold Member

  • Admin
  • 6,789 posts

Posted 25 June 2025 - 02:20 AM

Hi,

For your application and sensitive products, let you consider those papers.

Breizh

Attached Files



#3 lanco

lanco

    Brand New Member

  • Members
  • 4 posts

Posted 25 June 2025 - 01:28 PM

Thank you Breizh for the information shared.

It is not a difficult evaporation, an agitated film evaporator is not necessary, I think a climbing film evaporator is suitable.



#4 breizh

breizh

    Gold Member

  • Admin
  • 6,789 posts

Posted 25 June 2025 - 06:07 PM

Hi,

Let you try our best friend Google; I did not find much.

 

Reading my old notes (Uni time) I found a reference for vertical tubes, HSU and WESTWATER equation.

 

h=0.002 *Re^0.6*(lambdav^3*Rov*(Rol -Rov)*g/Muv^2) ^.333

with lamdav =thermal conductivity vapor, Ro density liquid and vapor ,Muv : viscosity vapor.

 

800< Re <5000

Re calculated at the exit of the pipe based on vapor stream.

 

 

As a general rule, heat transfer coefficients are within the range 100 to 250 kcal/h m2 C.

Good luck

Breizh

Attached Files



#5 lanco

lanco

    Brand New Member

  • Members
  • 4 posts

Posted 26 June 2025 - 02:43 PM

Thanks again.


Edited by lanco, 26 June 2025 - 02:44 PM.


#6 breizh

breizh

    Gold Member

  • Admin
  • 6,789 posts

Posted 26 June 2025 - 06:07 PM

HI,

The last resource on hands shared with you and others.

Review Chapter 5 Wolverine to support your work. This book was downloadable from Internet years ago. 

Key words: Wolverine engineering data book 

BTW Did you try Pery's chemical engineers' handbook?

EDIT : Extract from Process Heat transfer Robert W Serth

Breizh

Attached Files



#7 lanco

lanco

    Brand New Member

  • Members
  • 4 posts

Posted 06 July 2025 - 11:35 PM

Thank you so much Breizh



#8 EnggExp

EnggExp

    Junior Member

  • Members
  • 10 posts

Posted 14 July 2025 - 10:35 PM

In Perry’s, Section 5-58 through 5-64 covers boiling and evaporation in vertical tubes, which includes:
• Nusselt’s theory for laminar film condensation (useful as a baseline).
• Heat transfer correlations for vertical tube evaporators, specifically:
h = 0.943 \left( \frac{\rho_l (\rho_l - \rho_v) g h_{fg} k_l^3}{\mu_l L (T_{sat} - T_w)} \right)^{1/4}
For laminar film condensation, but modified for boiling and evaporation using correction factors.
• For rising film evaporators, refer to empirical correlations such as:
\text{Nu} = C \cdot \text{Re}^m \cdot \text{Pr}^n
where values of C, m, and n are given for different regimes (laminar, turbulent, etc.) and flow orientations (upward, boiling, film).
• Section includes detailed tables and graphs for organic liquids, aqueous solutions, and heat transfer coefficients for evaporating flows inside vertical tubes under various conditions.


Special Notes for Organic Solutions:
• Organic fluids often have lower thermal conductivities and viscosities than water, influencing h.
• Perry’s suggests using fluid-specific property tables and adjusting correlations for:
• Viscosity correction factors
• Boiling point elevation
• Wall superheat effects (important in falling or rising film operations)



Where to Look in Perry’s Handbook:
• Table 5-39 through Table 5-41: Properties for various organic and inorganic solutions.
• Section 5-58 to 5-64: Boiling inside tubes and evaporator design.

For a practical and conservative design of a rising film evaporator, use:
• Zuber-type correlations for boiling inside tubes if vapor formation is vigorous.
• Wilson or Chen correlations if you expect significant subcooled boiling followed by annular flow.

#9 EnggExp

EnggExp

    Junior Member

  • Members
  • 10 posts

Posted 14 July 2025 - 10:48 PM

Heat Transfer Coefficient Estimation in Vertical Tubes (Relevant to Rising Film)
Book: Process Heat Transfer: Principles, Applications and Rules of Thumb

From Chapter 9.5:
• Chen correlation:
h_b = S_{\text{CH}} h_{\text{nb}} + F(X_{tt}) h_L
• Includes nucleate + convective boiling
• Uses suppression factor due to flow
• Gungor–Winterton correlation:
Also additive but includes more accurate enhancement factors for boiling number and Lockhart-Martinelli parameter X_{tt}
• Liu–Winterton correlation:
h_b = \left[(S_{LW} h_{\text{nb}})^2 + (E_{LW} h_L)^2\right]^{1/2}
• More accurate for refrigerants and organic fluids

Best fit for your case:
Since you’re working with organic solutions and likely in low-pressure boiling regimes, Liu–Winterton or Gungor–Winterton is recommended over Chen due to broader data fit and better reliability for such fluids .



2. Boiling Regimes in Vertical Tubes

Figure 9.3 and section 9.5.1 describe how fluid transitions through boiling regimes in vertical tubes:
• Bubbly → Slug → Annular → Mist
• Heat transfer increases until dryout, where it drops significantly
• Rising film evaporators should be kept below the mist regime to avoid poor heat transfer

Design Implication:
Maintain moderate vapor fraction and avoid over-evaporation. You want to stay in the annular flow regime, where heat transfer is high but wall drying hasn’t occurred yet.



3. Critical Heat Flux (CHF) Concerns

If you exceed the optimal heat flux, CHF occurs leading to:
• Wall dryout
• Sharp drop in heat transfer
• Possible tube burnout

Palen’s correlation (Eq. 9.84b) gives:
\hat{q}_c = 23,660 \left(\frac{D^2}{L}\right)^{-0.35} P_c^{0.61} P_r^{0.25}(1 - P_r)

Use this to set the upper heat flux limit in your design.



4. Practical Engineering Use

If you lack precise experimental parameters:
• Use Dittus-Boelter for h_L
• Use Cooper or Mostinski for h_{nb}
• Then apply Liu–Winterton for combined coefficient




Reply to this topic



  

Similar Topics