System for calculating temperature of fluid inside pipe by using heat flux, outer surface temperature of pipe, and flow velocity of fluid

A system for calculating a temperature of a fluid inside a pipe by using a heat flux, an outer surface temperature of the pipe, and a flow velocity of the fluid, the system comprising:

• a flow meter to measure the flow velocity of the fluid flowing inside the pipe;
• a heat flux meter to measure the heat flux passing through an outer surface of the pipe, wherein the heat flux meter is disposed on an outer surface of the pipe;
• a thermometer to measure the outer surface temperature of the pipe, wherein the thermometer is disposed on an outer surface of the pipe;
• a calculator configured to calculate an internal fluid temperature, which is the temperature of the fluid flowing inside the pipe, by using the flow velocity of the fluid measured by the flow meter, the heat flux measured by the heat flux meter, and the outer surface temperature of the pipe measured by the thermometer;
• a determination module configured to determine whether the internal fluid temperature calculated by the calculator is within a preset temperature range between a first temperature and a second temperature;
• and
• a processor configured to, when the internal fluid temperature determined by the determination module is out of the preset temperature range, control the internal fluid temperature to be maintained within the preset temperature range,
• wherein the calculator is further configured to calculate the internal fluid temperature by using a calculation algorithm that is pre-trained based on an internal fluid temperature equation
• T
• b
• =
• R
• o
• R
• i
• ⁢
• q
• s
• h
• +
• q
• s
• ⁢
• R
• o
• ⁢
• ln
• ⁢
• (
• R
• o
• /
• R
• i
• )
• k
• +
• T
• o
• wherein Tb denotes the internal fluid temperature, Ro denotes a radius of an outer diameter of the pipe, Ri denotes a radius of an inner diameter of the pipe, qs denotes the heat flux passing through the outer surface of the pipe, h denotes a heat transfer coefficient of an internal fluid, k denotes thermal conductivity of the pipe, and To denotes the outer surface temperature of the pipe,
• wherein the calculation algorithm calculates and stores the heat transfer coefficient of the internal fluid in advance, by using an equation
• h
• =
• Nu
• ⁢
• x
• d
• i
• for the heat transfer coefficient of the internal fluid, a Nusselt number equation, which is any one selected from among Nu=4.36, Nu=3.66, Nu=0.023(Re0.8Prn), and Nu=5.0+0.025(RePr)0.8 according to a type and a state of the internal fluid, a Reynolds number equation
• Re
• =
• ρ
• ⁢
• υ
• ⁢
• d
• i
• μ
• ,
• and a Prandtl number equation
• pr
• =
• c
• p
• ⁢
• μ
• x
• ,
• wherein Nu denotes a Nusselt number, di denotes a diameter of the inner diameter of the pipe, χ denotes thermal conductivity of the internal fluid, Re denotes a Reynolds number, Pr denotes a Prandtl number, ρ denotes density of the internal fluid, v denotes a flow velocity inside the pipe, μ denotes a viscosity coefficient of the internal fluid, and Cp denotes specific heat of the internal fluid, and
• wherein the calculation algorithm calculates the heat transfer coefficient of the internal fluid by applying Nu=4.36 when the internal fluid flowing inside the pipe is a laminar flow and a magnitude of a heat flux discharged to the outside of the pipe is constant, applying Nu=3.66 when the internal fluid flowing inside the pipe is a laminar flow and the outer surface temperature of the pipe is constant, applying Nu=0.023(Re0.8Prn) when the internal fluid flowing inside the pipe is a turbulent flow, applying Nu=5.0+0.025(RePr)0.8 when the internal fluid flowing inside the pipe is a liquid metal, applying n=0.4 when a temperature of the pipe is greater than an external temperature of the pipe, and applying n=0.3 when the temperature of the pipe is less than the external temperature of the pipe.