Heating time
The steps to calculate the time required to heat a pipe, including the necessary parameters like the specific heat capacity of the material and the mass of the pipe. We will use the heat transfer formula to calculate the time.
Steps for Calculation:
- Calculate the volume of the pipe (V)
V = π ⋅ (Di/2)^2 ⋅ L
Where:
- Di is the inner diameter of the pipe (m)
- L is the length of the pipe (m)
2. Calculate the mass of the pipe (m)
m = ρ⋅V
Where:
- ρ is the density of the material (kg/m³)
3. Calculate the amount of heat required (Q)
Q = m⋅c⋅ΔT
Where:
- c is the specific heat capacity of the material (J/kg·°C)
- ΔT is the temperature change (°C)
4. Calculate the time (t)
t = Q / P
Where:
- P is the power supplied to the pipe (W)
Table showing the density of carbon steel and stainless steels 304 and 316
| Material | Density (kg/m³) |
| Carbon Steel | 7850 |
| Stainless Steel 304 | 8000 |
| Stainless Steel 316 | 8000 |
Table showing the specific heat capacity of carbon steel and stainless steels 304 and 316
| Material | Specific Heat Capacity (J/kg·°C) |
| Carbon Steel | 490-510 |
| Stainless Steel 304 | 500 |
| Stainless Steel 316 | 500 |
To calculate the time required to heat a steel pipe from 20°C to 50°C with a heat power of 20 W/m, we’ll follow these steps:
Given:
- Heat power: 20 W/m
- Initial temperature: 20°C
- Desired temperature: 50°C
- Pipe length: 1 m
- Inner diameter of the pipe: 0.1 m (or 10 cm)
- Density of steel: 7850 kg/m³
- Specific heat capacity of steel: 500 J/kg·°C
Calculation:
1. Calculate the volume of the pipe (V):
V = π⋅(Di/2)2⋅L = π⋅(0.1/2)^2⋅1 = π⋅0.05^2⋅1 = π⋅0.0025 = 0.00785 m3
2. Calculate the mass of the pipe (m):
m = ρ⋅V= 7850kg/m3⋅0.00785m3 = 61.6225kg
3. Calculate the amount of heat required (Q):
Q = m⋅c⋅ΔT = 61.6225kg ⋅ 500J/kg\cdotp°C ⋅ (50−20)°C
Q = 61.6225 ⋅ 500⋅30 = 924337.5 J
4. Calculate the time (t):
t = Q/P = (924337.5J )/ (20W/m ⋅ 1m) = 924337.5/20 = 46216.875s
t = (46216.875s) / (3600s/h) ≈ 12.83 hours
Therefore, to heat the pipe from 20°C to 50°C for a steel pipe with a length of 1 meter, using a heat power of 20 W/m, it will take approximately 12.83 hours (or about 12 hours and 50 minutes)