8 replies to this topic

[lanco]

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.

[breizh]

Hi,

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

Breizh

Attached Files

•  evaporation of difficult products.pdf   2.5MB   53 downloads
•  agitated film evaporator.pdf   1.55MB   46 downloads

[lanco]

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.

[breizh]

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

•  Evaporator_Handbook_10003_01_08_2008_US.pdf   2.43MB   45 downloads

[lanco]

Thanks again.

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

[breizh]

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

•  Process Heat Transfer. Principles, Applications and Rules of Thumb,2nd ed,2014.pdf   1.44MB   80 downloads
•  A Heat Transfer Textbook-Fifth Edition-Phlogiston Press-Cambridge-Massachusetts.pdf   28.86MB   44 downloads
•  ch5_4.pdf   56.76KB   33 downloads
•  db3ch10.pdf   275.64KB   70 downloads
•  ch5_3.pdf   440.75KB   45 downloads

[lanco]

Thank you so much Breizh

[EnggExp]

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.

[EnggExp]

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