Urgent natural gas calorific value calculation formula, thank you!

Q = VQQ is heat, q is calorific value, M is mass of solid fuel, V is volume of gas fuel, reference coefficient of conversion of various energy into standard coal energy name average low calorific value converted into standard coal coefficient raw coal 20934 kJ / kg 0.7143 kg standard coal / kg washed coal 26377 kJ / kg 0.90

Calculation formula of heating pipe diameter and heating area

The heating pipe diameter is calculated according to the flow rate and flow rate. Generally, the hot water flow rate is not more than 2 m / s as the calculation basis. D = 18.8 * root sign (V / ω), where D is the inner diameter mm; V is the hot water flow rate m3 / h; ω flow rate M / S;
Heating area is calculated according to heating capacity and heating index, which is generally 60W per square meter

Is there any relationship between water pressure and pipe diameter? What is the formula?

1 - suppose that in the static case, the
P=P0+ρ*g*(z1-z2)
Where P0 is the pressure on the water surface and z1-z2 is the height difference
According to the formula, the pressure is only related to the height difference and the initial pressure, and has nothing to do with the pipe diameter
2-assumption is that at low flow rate, the influence of viscosity can be ignored, and the physical parameters can be calculated according to the ideal fluid. It is assumed that the water flow velocity is uniform (that is, the water flow velocity is the same at all positions in the pipe diameter), and the water flow is assumed to be laminar
If Bernoulli equation is simplified, the following results can be obtained
P2-p1 = k * ρ * (U1 square - U2 Square)
Where p is the pressure at the front and rear end of the pipe, u is the velocity at the front and rear end of the pipe, and K is the correction factor. Considering the resistance loss of the pipe wall and the effect of the pipe wall on the fluid, the value is 0.4 ~ 0.88, which depends on the situation and needs to be determined by experiment
If there is potential energy difference, the potential energy at the front and rear ends should be substituted into the conservation equation
It can be seen that the water pressure is related to the pipe diameter, the flow velocity and the wall resistance,
3 - when the flow rate is fast, the situation is more complicated, which is not detailed here, but it can be inferred that it is related to the pipe diameter

Urgent natural gas calorific value calculation formula, thank you!