Surface temperature calclulation during pulsed laser irradiation

In summary: This is how some researchers may calculate the temperature in Celsius. In summary, to calculate the temperature increase on the surface of a copper bar during a NdYAG laser pulse, you will need to use the heat transfer equation and the given values for reflectance, thermal conductivity, and thermal diffusivity. You will also need to know the beam profile and initial conditions. Once you have solved the equation, you can convert the resulting temperature values from Kelvin to Celsius to obtain the temperature in Celsius.
  • #1
edi70
1
0
Dear all

I ahev a urgent problem!


I have a bar of copper metal and I irradiated it with a Gaussian beam of NdYAG laser at 532 nm with fluence 0.4 J/cm^2 and 6 ns pulse duration.
The reflectance of the copper in this wavelength is r= 0.61
The thermal conductivity of copper is k= 4 W/cmK
The thermal diffusivity is α=1,17cm^2/s
How can I calculate the temperature increase, in and on the surface, during the laser pulse?

How can I input the beam profile into the temperature equation
And of course to tell me what will be the temperature at the surface of the copper?

Some researchers calculate the temperature in Celsius, where the thermal conductivity units are W/cm K. Because of Kelvin=273+Celcious, I don’t know how they come to the occlusion that the outcome is in Celsius??

Thank for yout aswer in advance
EDI
 
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  • #2
To calculate the temperature increase of the copper during the laser pulse, you will need to use the heat transfer equation. This equation is given by: dT/dt = (1/(ρ*C))*(-k*(∂^2T)/(∂x^2) + q(x,t)) where ρ is the material density, C is the specific heat capacity, k is the thermal conductivity, and q(x,t) is the energy source in the form of a Gaussian beam. To solve this equation you will need to know the beam profile and initial conditions.Once you have solved the equation, you can convert the resulting temperature values from Kelvin to Celsius by subtracting 273.15 from the temperature values in Kelvin.
 

1. How is surface temperature calculated during pulsed laser irradiation?

The surface temperature during pulsed laser irradiation can be calculated using the following equation: Ts = T0 + (F*τ)/k, where Ts is the surface temperature, T0 is the initial temperature, F is the laser fluence, τ is the pulse duration, and k is the thermal conductivity of the material.

2. What factors affect the accuracy of surface temperature calculation during pulsed laser irradiation?

The accuracy of surface temperature calculation during pulsed laser irradiation can be affected by factors such as the material properties (thermal conductivity, specific heat, etc.), laser parameters (fluence, wavelength, pulse duration), and experimental conditions (environmental temperature, sample geometry, etc.).

3. Can surface temperature be measured during pulsed laser irradiation?

Yes, surface temperature can be measured during pulsed laser irradiation using techniques such as infrared thermography, thermocouples, or pyrometers. These methods can provide real-time temperature data and can be used to validate the calculated surface temperature.

4. How does the laser fluence affect surface temperature during pulsed laser irradiation?

The laser fluence has a direct impact on the surface temperature during pulsed laser irradiation. Higher laser fluence will result in a higher surface temperature due to increased energy absorption and heat generation in the material. Therefore, it is important to carefully choose the laser fluence for accurate surface temperature calculation.

5. Is surface temperature calculation during pulsed laser irradiation applicable to all materials?

No, surface temperature calculation during pulsed laser irradiation may not be applicable to all materials. The accuracy of the calculation depends on the material properties and their response to laser irradiation. It is recommended to perform a sensitivity analysis and validate the results with experimental data for each material before using this calculation method.

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