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Hot Pipeline Temperature Decay Curve

Calculate high temperature pipeline temperature decay curve from thermal properties or temperature data.

The temperature is assumed to decay exponentially. The temperature decay can be defined by either a decay length, or decay time. The decay length is only valid provided that the fluid mass flow rate and heat capacity are unchanged. The decay time is valid for any flowrate provided that the fluid heat capacity is unchanged. The overall heat transfer coefficient is calculated relative to the inside diameter of the pipe.

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CALCULATOR : High Temperature Pipeline Temperature Profile From Thermal Properties (Multi Layer Pipe) [PLUS]   ±

Calculate high temperature pipeline temperature profile and temperature decay constants from thermal properties and fluid flow rate for multi layer pipelines.

The decay length is only valid provided that the fluid mass flow rate and heat capacity are unchanged. The decay time is valid for any flowrate provided that the fluid heat capacity is unchanged. The overall heat transfer coefficient is calculated relative to the inside diameter of the pipe. The fluid flow rate can be defined either by fluid velocity, fluid volume flow rate, or fluid mass flow rate. thermal resistance does not include external film resistance (internal film resistance is included). Use the decay constant calculator to calculate thermal resistance including external film resistance.

Tool Input

  • schdtype : Line Pipe Schedule Type
  • diamtype : Line Pipe Diameter Type
    • ODu : User Defined Outside Diameter
    • IDu : User Defined Inside Diameter
  • wtntype : Line Pipe Wall Thickness Type
    • tnu : User Defined Wall Thickness
  • flowtype : Fluid Flow Type
    • Qfu : User Defined Volume Flow Rate
    • Mfu : User Defined Mass Flow Rate
    • Vfu : User Defined Fluid Velocity
  • hrstype : Soil Cover Type
  • sectype : Cross Section Type
    • OODu : User Defined Outer Diameter Including Coatings)
    • Ru : User Defined Total Thermal Resistance
  • lctype : Decay Length Type
    • Lu* : User Defined Decay Length
    • Tu* : User Defined Decay Time
  • WTi : Pipe Liner Wall Thickness
  • Ki : Pipe And Liner Thermal Conductivity
  • WTo : Pipe Coating Wall Thickness
  • Ko : Pipe Coating Thermal Conductivity
  • X : Position Along Pipe
  • L : Pipeline Length
  • Ti : Inlet Temperature
  • Ta : Ambient Temperature
  • ρf : Fluid Density
  • Cpf : Fluid Specific Heat Capacity
  • Kf : Internal Fluid Thermal Conductivity
  • μf : Internal Fluid Dynamic Viscosity
  • H : Soil Cover Height To Top Of Pipe
  • Ks : Soil Heat Conductivity

Tool Output

  • ΔT : Delta Temperature At Inlet
  • IID : Pipe Inside Diameter Including Liner
  • L* : Decay Length
  • Mf : Fluid Mass Flow Rate
  • OD : Line Pipe Diameter
  • OD/tn : Line Pipe Diameter Over Wall Thickness Ratio
  • OOD : Pipe Outer Diameter Including Coatings
  • Qf : Fluid Volume Flowrate
  • R : Total Thermal Resistance
  • Rfi : Internal Film Thermal Resistance
  • Rp : Pipe Thermal Resistance
  • Rs : Soil Thermal Resistance
  • T* : Decay Time
  • To : Outlet Temperature
  • Tx : Temperature At X
  • U : Overall Heat Transfer Coefficient (On IID)
  • Vf : Fluid Velocity
  • tn : Line Pipe Thickness

CALCULATOR : High Temperature Pipeline Temperature Profile From Temperature Data Points [PLUS]   ±

Calculate high temperature pipeline temperature profile and temperature decay constants from temperature data.

Enter temperature data points as comma separated pairs (position, temperature), with each pair on a new line. Change units on the setup page. The temperature profile is assumed to be exponential. Temperature data points should be either all above the ambient temperature (cooling), or all below the ambient temperature (heating). Avoid temperature data points close to the ambient temperature.

The overall heat transfer coefficient and the decay time are calculated from the fluid density, flow rate and heat capacity.

The decay length is only valid provided that the fluid mass flow rate and heat capacity are unchanged. The decay time is valid for any flowrate provided that the fluid heat capacity is unchanged. The overall heat transfer coefficient is calculated relative to the inside diameter of the pipe.

Tool Input

  • schdtype : Line Pipe Schedule Type
  • diamtype : Diameter Type
    • ODu : User Defined Outside Diameter
    • IDu : User Defined Inside Diameter
  • wtntype : Wall Thickness Type
    • tnu : User Defined Wall Thickness
  • zutype : Temperature Decay Type
  • flowtype : Fluid Flow Rate Type
    • Qfu : User Defined Volume Flow Rate
    • Mfu : User Defined Mass Flow Rate
    • Vfu : User Defined Fluid Velocity
  • sectype : Pipe Section Properties Type
  • WTi : Pipe Liner Wall Thickness
  • Xdata : X Position Data Values
  • Tdata : T Temperature Data Values
  • Ta : Ambient Temperature
  • X : Distance From Inlet
  • L : Pipeline Length
  • ρf : Fluid Density
  • Cpf : Fluid Heat Capacity

Tool Output

  • ΔT : Delta Temperature At Inlet
  • IID : Pipe Inner Diameter (Including Liner)
  • L* : Decay Length
  • Mf : Fluid Mass Flow Rate
  • OD : Nominal Outside Diameter
  • OD/tn : Pipe Diameter Over Line Pipe Wall Thickness Ratio
  • Qf : Fluid Volume Flow Rate
  • R : Total Thermal Resistance
  • T* : Decay Time
  • Ti : Inlet Temperature
  • To : Outlet Temperature
  • Tu : Unit Temperature Value (1 = Cooling -1 = Heating)
  • Tx : Temperature At X
  • U : Overall Heat Transfer Coefficient (From ID)
  • Vf : Fluid Velocity
  • a : Regression Slope
  • b : Regression Y Intercept
  • tn : Nominal Wall Thickness

CALCULATOR : High Temperature Pipeline Temperature Decay Constants (Multi Layer Pipe) [PLUS]   ±

Calculate high temperature pipeline temperature decay constants from thermal properties and fluid flow rate for multi layer pipelines, and including internal and external film resistance.

For insulated pipelines and buried pipelines, the internal and external film resistance can often be ignored which provides a simpler calculation. However in some cases the film resistance is required. The internal film resistance can be used for either cooling or heating. The external film resistance should be used for cooling. Use the options with no film resistance to determine whether film resistance is required.

The decay length is only valid provided that the fluid mass flow rate and heat capacity are unchanged. The decay time is valid for any flowrate provided that the fluid heat capacity is unchanged. The overall heat transfer coefficient is calculated relative to the inside diameter of the pipe. The fluid flow rate can be defined either by fluid velocity, fluid volume flow rate, or fluid mass flow rate.

Tool Input

  • schdtype : Line Pipe Schedule Type
  • diamtype : Line Pipe Diameter Type
    • ODu : User Defined Outside Diameter
    • IDu : User Defined Inside Diameter
  • wtntype : Line Pipe Wall Thickness Type
    • tnu : User Defined Wall Thickness
  • flowtype : Internal Fluid Flow Type
    • Qfu : User Defined Volume Flow Rate
    • Mfu : User Defined Mass Flow Rate
    • Vfu : User Defined Fluid Velocity
  • sectype : Cross Section Type
    • OODu : User Defined Outer Diameter Including Coatings)
    • Ru : User Defined Total Thermal Resistance
  • hrftype : Thermal Resistance Type
  • lctype : Decay Constant Type
    • Lu* : User Defined Decay Length
    • Tu* : User Defined Decay Time
  • WTi : Pipe Liner Wall Thickness
  • Ki : Pipe And Liner Thermal Conductivity
  • WTo : Pipe Coating Wall Thickness
  • Ko : Pipe Coating Thermal Conductivity
  • Ti : Internal Fluid Temperature
  • Ta : External Fluid Ambient Temperature
  • ρf : Internal Fluid Density
  • Cpf : Internal Fluid Specific Heat Capacity
  • Kf : Internal Fluid Heat Conductivity
  • μf : Internal Fluid Dynamic Viscosity
  • ρe : External Fluid Density
  • Cpe : External Fluid Specific Heat Capacity
  • Ke : External Fluid Heat Conductivity
  • μe : External Fluid Dynamic Viscosity
  • βe : External Fluid Expansion Coefficient (Free Convection)
  • Ve : External Fluid Velocity
  • H : Soil Cover Height To Top Of Pipe
  • Ks : Soil Heat Conductivity

Tool Output

  • ΔT : Delta Temperature At Inlet
  • IID : Pipe Inner Diameter Including Liner
  • L* : Decay Length
  • Mf : Internal Fluid Mass Flow Rate
  • OD : Line Pipe Diameter
  • OD/tn : Line Pipe Diameter Over Wall Thickness Ratio
  • OOD : Pipe Outer Diameter Including Coatings
  • Qf : Internal Fluid Volume Flowrate
  • R : Total Thermal Resistance
  • Rfi : Internal Film Thermal Resistance
  • Rfo : External Film Thermal Resistance
  • Rp : Pipe Thermal Resistance
  • Rs : Soil Thermal Resistance
  • T* : Decay Time
  • U : Overall Heat Transfer Coefficient (On IID)
  • Vf : Internal Fluid Velocity
  • tn : Line Pipe Thickness

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