## HTRI Design Manual

The Design Manual is the comprehensive reference for HTRI’s thermal design recommendations for all types of heat exchangers. This electronic document summarizes calculation methods in HTRI software, provides design recommendations, and offers practical design tips. Topics covered include basic methods for single-phase pressure drop and heat transfer, condensation, boiling, two-phase flow, fouling, flow-induced vibration, and design guidelines for shell-and-tube, air-cooled, and non-tubular exchangers. It provides the basis for understanding HTRI software results and contains references to research reports for detailed study.

Volume A Contents

A1 Purpose and organization

A1.1 General description

A1.2 Suggested uses

A1.3 Organization

A2 Unit conversions

A2.1 Definitions

A2.2 Conventions

Volume B Contents

B1 Principles of heat transfer

B1.1 Principles of heat transfer processes

B1.2 Overall heat transfer coefficient and supporting calculations

B1.2.1 Fourier’s Law concepts
B1.2.2 Driving force and resistance concept
B1.2.3 Derivation of overall heat transfer coefficient, U
B1.2.4 Derivation of tube wall temperature, Tw
B1.2.5 Average bulk temperature

B1.3 Mean temperature difference

B1.3.1 Exact and integrated solution
B1.3.2 Flow arrangements
B1.3.3 Graphical solutions
B1.3.4 Mean temperature difference graphs for shell-and-tube exchangers
B1.3.5 Mean temperature difference graphs for crossflow arrangements

B1.4 Nomenclature

B2 Single-phase pressure drop

B2.1 Pressure drop inside conduits of constant cross section

B2.1.1 Flow inside tubes
B2.1.2 Flow inside tubes with twisted tape inserts
B2.1.3 Flow inside tubes with internal fins
B2.1.4 In annuli
B2.1.5 Axial flow in tube bundles with rod-type tube supports

B2.2 Pressure drop across plain tube banks

B2.2.1 Basic geometry
B2.2.2 Isothermal flow
B2.2.3 Nonisothermal flow
B2.2.4 Calculated example, plain tubes

B2.3 Pressure drop across low-finned tube banks

B2.3.1 Basic geometry
B2.3.2 Friction factor correction
B2.3.3 Nonisothermal correction
B2.3.4 Pressure drop
B2.3.5 Calculated example, low-finned tubes, 19 fins/in.

B2.4 Pressure drop across high-finned tube banks

B2.4.1 Definitions and limitations
B2.4.2 Friction factor definition
B2.4.3 General correlation
B2.4.4 Nonequilateral staggered layouts
B2.4.5 Nonsquare inline layouts
B2.4.6 Special finned tubes
B2.4.7 ESCOA correlations for pressure drop

B2.5 Pressure drop in plate-and-frame exchangers

B2.5.1 Typical plate-and-frame configuration
B2.5.2 Pressure drop estimation method

B2.6 Pressure drop in spiral plate heat exchangers

B2.6.1 Pressure drop estimation method
B2.6.2 Range of data and accuracy

B2.7 Pressure drop in bends

B2.7.1 Secondary flow
B2.7.2 Classification of bends
B2.7.3 Loss coefficient methods

B2.8 Pressure drop across tube bundles with continuous fins

B2.8.1 Pressure drop method for vapors
B2.8.2 Pressure drop estimation method for liquids

B2.9 Nomenclature

B3 Single-phase heat transfer

B3.1 Heat transfer inside conduits of constant cross section

B3.1.1 Inside plain tubes
B3.1.2 Inside tubes with twisted tape inserts
B3.1.3 Inside tubes with internal fins
B3.1.4 In annuli
B3.1.5 Axial flow in tube bundles with rod-type tube supports

B3.2 Heat transfer, plain tube banks

B3.2.1 Basic correlation
B3.2.2 Curve fit equation for (ji)10
B3.2.3 Tuberow correction
B3.2.4 Alternative form for turbulent flow
B3.2.5 Baffled heat exchanger window heat transfer
B3.2.6 Calculated example, plain tubes

B3.3 Heat transfer, low-finned tube banks

B3.3.1 Basic geometry low-finned tubes
B3.3.2 Heat transfer, j-factor correlation
B3.3.3 Fin efficiency

B3.4 Heat transfer, high-finned tube banks

B3.4.1 Definitions and limitations
B3.4.2 Area calculations
B3.4.3 Colburn j-factor definition
B3.4.4 Smooth-finned tubes in staggered layouts
B3.4.5 Segmented-finned tubes in staggered layouts
B3.4.6 Finned tubes in inline layouts
B3.4.7 Special finned tubes
B3.4.8 Fin efficiency
B3.4.9 Fin bond resistance
B3.4.10 ESCOA correlations for heat transfer

B3.5 Heat transfer in plate-and-frame exchangers

B3.5.1 General information
B3.5.2 Typical plate-and-frame configuration
B3.5.3 Heat transfer estimation model
B3.5.4 Example calculation, waste heat recovery plate heat exchanger
B3.5.5 Effect of flow distribution on heat transfer

B3.6 Heat transfer in spiral plate heat exchangers

B3.6.1 Heat transfer estimation method
B3.6.2 Range of data and accuracy

B3.7 Heat transfer across tube bundles with continuous fins

B3.7.1 Heat transfer method for vapors
B3.7.2 Heat transfer method for liquids

B3.8 Nomenclature

B4 Condensation

B4.1 Principles of condensation

B4.1.1 Filmwise condensation
B4.1.2 Flow regimes
B4.1.3 Condensate film heat transfer coefficients
B4.1.4 Vapor-phase heat transfer coefficient
B4.1.5 Desuperheating
B4.1.6 Subcooling
B4.1.7 Mean temperature difference
B4.1.8 Incrementation and short-cut procedures

B4.2 Condensation of pure vapors inside vertical tubes

B4.2.1 Gravity-controlled flow
B4.2.2 Shear-controlled flow
B4.2.3 Annular-mist flow
B4.2.4 Heat transfer coefficient selection

B4.3 Condensation of pure vapors inside horizontal tubes

B4.3.1 Shear-controlled flow, annular pattern
B4.3.2 Shear-controlled flow, mist pattern
B4.3.3 Gravity-controlled flow, wave and stratified patterns
B4.3.4 Transition between annular and semi-annular flow
B4.3.5 Transition between shear- and gravity-controlled flow
B4.3.6 Slug and plug flow patterns
B4.3.7 Heat transfer coefficient selection

B4.4 Condensation of pure vapors outside horizontal plain tube bundles

B4.4.1 Gravity-controlled flow
B4.4.2 Shear-controlled flow
B4.4.3 Slug-plug flow
B4.4.4 Heat transfer coefficient selection

B4.5 Condensation of pure vapors outside baffled vertical plain tube bundles

B4.5.1 Flow regime considerations
B4.5.2 Gravity-controlled flow
B4.5.3 Shear-controlled flow

B4.6 Condensation of mixed vapors and vapor-gas mixtures

B4.6.1 Theory
B4.6.2 Resistance Proration Method
B4.6.3 Composition Profile Method
B4.6.4 Methods for tubeside condensation
B4.6.5 Methods for shellside condensation

B4.7 Condensation on finned tubes in horizontal tube bundles

B4.7.1 Gravity-controlled flow
B4.7.2 Shear-controlled flow
B4.7.3 Heat transfer coefficient selection
B4.7.4 Fin efficiency
B4.7.5 Mixtures and non-condensables
B4.7.6 Rose-Briggs theoretical finned tube methods

B4.8 Subcooling

B4.8.1 Vertical condensers
B4.8.2 Horizontal condensers

B4.9 Desuperheating

B4.9.1 Dry-wall desuperheating
B4.9.2 Wet-wall desuperheating
B4.9.3 Wall temperature estimation

B4.10 Condensation of immiscible mixtures

B4.10.1 Heat transfer method
B4.10.2 Heat transfer calculation procedures
B4.10.3 Recommended methods

B4.11 Direct contact heat transfer

B4.11.1 Methods used for gas coolers
B4.11.2 Direct contact condensers
B4.11.3 Application of theoretical studies

B4.12 Fogging condensation

B4.12.1 Fogging principles
B4.12.2 Determination of supersaturation
B4.12.3 Critical supersaturation

B4.13 Reflux condensation

B4.13.1 Tubeside reflux condensation
B4.13.2 Shellside reflux condensation

B4.14 Enhanced condensation

B4.14.1 Enhanced condensation using tubeside inserts
B4.14.2 Condensation in micro-finned tubes

B4.15 Dehumidification of gases flowing outside high-finned tube bundles

B4.15.1 Mass Transfer Method
B4.15.2 Simplified RPM
B4.15.3 ARI Method

B4.16 Condensation heat transfer coefficient in plate-and-frame exchangers

B4.16.1 Condensation of pure vapors
B4.16.2 Condensation of mixtures

B5 Boiling

B5.1 Boiling process principles

B5.1.1 Introduction
B5.1.2 Pool boiling
B5.1.3 Flow boiling
B5.1.4 Onset of nucleate boiling

B5.2 Nucleate boiling outside single horizontal tubes

B5.2.1 Maximum heat flux, q1 max
B5.2.2 Nucleate boiling coefficient, hnb
B5.2.3 Natural convection heat transfer coefficient, hnc

B5.3 Flow boiling inside tubes

B5.3.1 Introduction
B5.3.2 Maximum heat flux and vapor fraction
B5.3.3 Wet-wall heat transfer methods
B5.3.4 Dry-wall heat transfer methods
B5.3.5 Twisted tape inserts
B5.3.6 Microfin tubes

B5.4 Flow boiling outside horizontal tube bundles

B5.4.1 Introduction
B5.4.2 Wet-wall heat transfer methods
B5.4.3 Dry-wall heat transfer methods

B5.5 Boiling with high vapor-phase resistance

B5.5.1 Introduction
B5.5.2 Background
B5.5.3 Recommended relations

B5.6 Film and transition boiling outside single horizontal tubes

B5.6.1 Film boiling minimum heat flux, qmin
B5.6.2 Minimum temperature difference for fully developed film boiling, DTq min
B5.6.3 Film boiling heat transfer coefficient, hfb
B5.6.4 Transition boiling heat transfer coefficient, htb

B5.7 Falling film evaporation inside vertical tubes

B5.7.1 Introduction
B5.7.2 General configuration
B5.7.3 Liquid distribution
B5.7.4 Tubeside heat transfer coefficients
B5.7.5 Film breakdown
B5.7.6 Flooding

B5.8 Flow boiling heat transfer coefficient in plate-and-frame exchangers

B5.8.1 Liquid film at wall
B5.8.2 Partial or complete dry wall

B6 Two-phase flow

B6.1 Basic relationships

B6.1.1 Homogeneous flow model
B6.1.2 Separated flow model

B6.2 Flow regimes

B6.2.1 Horizontal flow
B6.2.2 Vertical flow

B6.3 Flow limitations

B6.3.1 Flooding
B6.3.2 Entrainment
B6.3.3 Critical flow
B6.3.4 Example calculation

B6.4 Pressure drop

B6.4.1 General equation
B6.4.3 Momentum
B6.4.4 Friction
B6.4.5 Pressure drop across restrictions
B6.4.6 Boiling in plate-and-frame exchangers
B6.4.7 Pressure drop in bends

B6.5 Heat transfer

B6.5.1 Convective heat transfer coefficient for liquid film
B6.5.2 Effects of boiling and condensing
B6.5.3 Effects of vapor-phase resistance
B6.5.4 Feed-effluent exchangers

B6.6 Liquid-liquid two-phase systems

B6.6.1 Effective viscosity of immiscible liquid-liquid emulsions
B6.6.2 Heat transfer and pressure drop with immiscible liquid phases

B6.7 Solid-liquid two-phase systems

B6.7.1 General recommendations
B6.7.2 Heat transfer and pressure drop calculations
B6.7.3 Equipment selection

B6.8 Bitumen-water slurries

B6.8.1 Introduction
B6.8.2 General recommendations
B6.8.3 Pressure drop calculations
B6.8.4 Heat transfer calculations

Volume C Contents

C1 Practical aspects of heat exchanger design

C2 Heat transfer equipment types

C2.1 Construction data and geometry parameters

C2.1.1 Introduction
C2.1.2 Tube bundle design characteristics

C2.2 Condenser types

C2.2.1 Introduction
C2.2.2 Shellside condensers
C2.2.3 Tubeside condensers

C2.3 Reboiler types

C2.3.1 Introduction
C2.3.2 Kettle reboilers
C2.3.3 Internal reboilers
C2.3.4 Vertical thermosiphon reboilers
C2.3.5 Horizontal thermosiphon reboilers
C2.3.6 Pump-through reboilers
C2.3.7 Falling film reboilers

C2.4 Gasketed plate heat exchangers: Construction and operational principles

C2.4.1 Introduction
C2.4.2 Construction
C2.4.3 Construction materials and design codes
C2.4.4 Plate arrangements and other basic design principles
C2.4.5 General applications

C2.5 Air-cooled heat exchanger construction practices

C2.5.1 Introduction
C2.5.2 Description of air-cooled heat exchangers
C2.5.3 Air-cooled heat exchanger configurations
C2.5.4 Tube bundles
C2.5.5 Axial flow fans
C2.5.6 Plenum, fan deck, and fan ring construction
C2.5.7 Motor-fan drives
C2.5.8 Air flow in forced-draft
C2.5.9 Inert accumulation in air-cooled condensers

C2.6 Heat exchanger selection

C2.6.1 Introduction
C2.6.2 Important process parameters
C2.6.3 Important geometry paramenters
C2.6.4 Tubes
C2.6.5 Selection guides

C2.7 Nomenclature

C3 Shell-and-tube single-phase flow

C3.1 Shellside heat transfer and pressure drop by the Stream Analysis Method

C3.1.1 Introduction
C3.1.2 Flow distribution equations
C3.1.3 Pressure drop calculations
C3.1.4 Heat transfer calculations
C3.1.5 Mean temperature difference profile, d
C3.1.6 Probable accuracy
C3.1.7 Shellside heat transfer and pressure drop, helical baffles
C3.1.8 Disk-and-doughnut baffles
C3.1.9 Crossbaffles
C3.1.10 Shellside flow areas
C3.1.11 Number of tuberows crossed
C3.1.12 Shell exit flow areas
C3.1.13 Shell entrance flow areas
C3.1.14 Shellside heat transfer and pressure drop, strip baffles

C3.2 Pressure drop in tubeside nozzles and channels

C3.3 Pressure drop in shellside nozzles

C3.3.1 Introduction
C3.3.2 Standard nozzles
C3.3.3 Impingement plates
C3.3.4 Annular distributors
C3.3.5 Outlet distributor

C3.4 Longitudinal baffle leakage: F, G, H shells

C3.4.1 Introduction
C3.4.2 Thermal leakage
C3.4.3 Physical leakage
C3.4.4 Effect of physical leakage on heat transfer

C3.5 Exchanger weight estimation

C3.5.1 Bundle
C3.5.2 Shell body
C3.5.5 Tubeside nozzles
C3.5.6 Shellside nozzles
C3.5.7 Longitudinal baffle
C3.5.8 Total dry weight
C3.5.9 Weight filled with water

C3.6 Nomenclature

C4 Condensers

C4.1 Condenser design

C4.1.1 Selection of condenser type

C4.2 Vertical tubeside condensers

C4.2.1 Introduction
C4.2.2 Temperature profiles
C4.2.3 Flow regimes
C4.2.4 Condensing-side heat transfer
C4.2.5 Condensing-side pressure drop
C4.2.6 Coolant heat transfer and pressure drop

C4.3 Horizontal tubeside condensers

C4.3.1 Introduction
C4.3.2 Temperature profiles
C4.3.3 Flow regimes
C4.3.4 Condensing-side heat transfer
C4.3.5 Condensing-side pressure drop
C4.3.6 Effect of inclination
C4.3.7 Coolant heat transfer and pressure drop

C4.4 Horizontal shellside plain-tube condensers

C4.4.1 Introduction
C4.4.2 Temperature profiles
C4.4.3 Flow regimes
C4.4.4 Condensing-side heat transfer
C4.4.5 Condensing-side pressure drop
C4.4.6 Condensate drainage
C4.4.7 Venting
C4.4.8 Coolant heat transfer and pressure drop

C4.5 Vertical shellside plain-tube condensers

C4.5.1 Introduction
C4.5.2 Temperature profiles
C4.5.3 Flow regimes
C4.5.4 Condensing-side heat transfer
C4.5.5 Condensate drainage
C4.5.6 Venting
C4.5.7 Coolant heat transfer and pressure drop

C4.6 Condensation in finned annulus of double-pipe heat exchanger

C4.7 Nomenclature

C5 Reboilers and vaporizers

C5.1 Kettle and internal reboiler design

C5.1.1 Introduction
C5.1.2 Maximum heat flux
C5.1.3 Nucleate regime, average boiling heat transfer coefficient, hab
C5.1.4 Film boiling
C5.1.5 Expected accuracy
C5.1.6 General design considerations
C5.1.7 Rating curve calculation procedure
C5.1.8 Kettle sizing and liquid entrainment
C5.1.9 Bundle circulation

C5.2 Horizontal shellside thermosiphon reboilers

C5.2.1 Introduction
C5.2.2 Maximum heat flux
C5.2.3 Average boiling heat transfer coefficient, hab
C5.2.4 Heating medium heat transfer coefficients
C5.2.5 Vapor fraction estimation

C5.3 Vertical tubeside thermosiphon reboilers

C5.3.1 Introduction
C5.3.2 Design heat flux, qdes
C5.3.3 Average boiling heat transfer coefficient, hab
C5.3.4 Circulation velocity and vapor fraction estimation
C5.3.5 Correction for subcooled liquid zone
C5.3.6 Mist flow vapor fraction
C5.3.7 Film boiling design
C5.3.8 Heating medium coefficient, hh
C5.3.9 Flow regimes
C5.3.10 Thermosiphon reboiler piping
C5.3.11 Two-phase flow instabilities in vertical thermosiphon reboilers

C5.4 Vertical shellside thermosiphon reboilers

C5.4.1 Introduction
C5.4.2 Circulation velocity and vapor fraction estimation
C5.4.3 Recommendations for good flow distribution
C5.4.4 Additional information on design and operation of waste heat boilers

C5.5 Forced-flow reboilers

C5.5.1 Introduction
C5.5.2 Flow rate and fraction vaporized
C5.5.3 Design heat flux
C5.5.4 Average boiling heat transfer coefficient, hab
C5.5.5 Tubeside flow distribution
C5.5.6 Shellside forced-flow boiling

C5.6 Falling film reboilers/evaporators

C5.6.1 Introduction
C5.6.2 Flow distribution
C5.6.3 Heat transfer coefficient and pressure drop
C5.6.4 Film breakdown

C5.7 Special design considerations

C5.7.1 Introduction
C5.7.2 Fouling
C5.7.3 Very wide boiling range mixtures
C5.7.4 Operation near critical pressure
C5.7.5 Operation in deep vacuum
C5.7.6 Sparging
C5.7.7 Very low DT
C5.7.8 Very high DT
C5.7.9 Shellside flow separation problems

C5.8 Effective mean temperature differences in reboilers

C5.8.1 Introduction
C5.8.2 Kettle or internal reboilers
C5.8.3 Vertical thermosiphon reboilers
C5.8.4 Horizontal thermosiphon reboilers
C5.8.5 Temperature profile calculation

C5.9 Spiral plate thermosiphon reboilers

C5.10 Boiling in finned annulus of double-pipe heat exchanger

C5.11 Nomenclature

C6 Fouling

C6.1 Fouling characteristics

C6.1.1 Types of fouling mechanisms
C6.1.2 Fouling categories defined
C6.1.3 General behavior of fouling processes
C6.1.4 Application to HTRI software

C6.2 Cooling water fouling predictive model

C6.2.1 Original HTRI empirical correlation
C6.2.2 Fouling model equation
C6.2.3 Evaluation of asymptotic fouling resistance
C6.2.4 Evaluation of fouling-time curve
C6.2.5 Application of constant heat flux model
C6.2.6 Typical asymptotic fouling curves

C6.3 Fouling deposit characteristics

C6.3.1 Characteristics of water fouling deposits
C6.3.2 Conductivity of fouling deposits

C6.4 Fouling with single-phase heavy organics

C6.4.1 Common misconceptions
C6.4.2 Threshold studies
C6.4.3 Surface and bulk temperature effects
C6.4.4 Velocity effects
C6.4.5 Bulk composition and chemistry
C6.4.6 Effect of salt in crude
C6.4.7 Effect of surface condition
C6.4.8 Flash drum

C6.5 Fouling in plate heat exchangers

C6.5.1 Effects of velocity and shear stress
C6.5.2 Experimental data and recommended values

C6.6 Fouling in reboilers

C6.6.1 Guidelines for minimizing fouling
C6.6.2 Start-up and control

C6.7 Analysis of crude oil fouling mechanisms

C6.7.2 Coking
C6.7.3 Corrosion
C6.7.4 Crystallization
C6.7.5 Insoluble gum formation
C6.7.6 Sedimentation fouling

C6.8 Shear stress in shell-and-tube heat exchangers

C6.8.1 Tubeside shear stress
C6.8.2 Shellside shear stress
C6.8.3 Shellside longitudinal flow shear stress

C6.9 Nomenclature

C7 Flow-induced vibration

C7.1 Flow-induced vibration analysis

C7.1.1 Introduction
C7.1.2 Vibration causes and effects
C7.1.3 Natural frequency of tubes
C7.1.4 Acoustic frequency of shell
C7.1.5 Shellside velocities for vibration analysis
C7.1.6 Vibration prediction methods

C7.2 Program results

C7.2.1 Introduction
C7.2.2 Interpretation of vibration analysis results

C7.3 Design improvements

C7.3.1 Introduction
C7.3.2 Tube vibration damage
C7.3.3 Acoustic vibration noise
C7.3.4 Other design considerations

C7.4 Troubleshooting and corrective actions

C7.5 Nomenclature