Tashkent, Mart 4-5, 2022 1-я международная научная конференция «Современное материаловедение: актуальные проблемы, достижении и инновации» Zamonaviy materialshunoslik: dolzarb

"Modern Materials Science: Topical Issues, Achievements and Innovations" (ISCMMSTIAI-2022) 
358 
D is the diffusion coefficient of iron ions in the pores of the layer of magnetite, m
2
/s; hD is the 
coefficient of their mass transfer in the core of the stream from the border of the oxide - the flow of 
hydrotransports, m/s. We define the values of the values included in equation (2): 
1. The coefficient of recalculation is determined from the expression of β = 3.6*106*τ
o
where τ
o
- the operation time of the heat network during the year, h. The value (τ
o
is taken equal to 
the duration of the heating period or, in the case of year-round operation of the network, taking into 
account its annual stop On scheduled repair (15 days), equal to 8400 hours. 
2. The coefficient q = q{d
i
) is a function obtained during the comparison of the average for the year 
of the calculated values to K, mm/year, with the internal corrosion rates obtained during the surveys of 
thermal conductors of various diameters, and smoothing the difference between them: q
=
2,1* 10
5
d
i
+1400. 
3.
The nature of the magnetite film, the fraction of the unit, is determined from the following system of 
equations:
0, 03 at t <15 °С; 
8 (i) = 0,15 — 0,8 10 
3
at 
t 
15 °С ≤ t ≤ 75 °С; 
0, 01 at t> 75 °С, 
where t
— disperse system temperature,
°С. 
2.
The coefficient D, m
2
/с , the diffusion of iron ions in the pores of the oxide and the coefficient of hD, 
m/с, their mass transfer into one-phase flow of the coolant during turbulent flow, respectively, in the works 
[2, 3]: 
𝐷 = 1·10
−15
273+𝑡
𝜇
(3) 
ℎ
𝐷
=
𝐷
𝑑
𝑖
(2,0 + 𝑎𝑅𝑒
𝑏
𝑆𝑐
1
3
)
(4)
where μ is the dynamic viscosity of dispersed systems, kg/(m-s); a = 0.86 - 10.00 / (4.70 - S
c
)
3
, B = 
0.0165 -0,011S
emp
(—S
c
) - empirical coefficients; Re and S
c
- Reynolds and Schmidt numbers, 
respectively, which are as follows:
R
e
=
ν∗d
i
∗ρ
μ
(5)
𝑆
c
=
μ
ρ∗
D
(6)
Where: 
𝜈 =
4𝐺
3600𝜋𝑑
𝑖
2
𝜌
𝑚/𝑠
(7) 
and ρ, kg/m
3
- speed and density of dispersed systems, respectively; G - digging dispersed systems, kg/h. 
For the convenience of calculations on the PC, the density ρ(t), kg/m
3
, and the viscosity μ (t), kg/(m*c), 
the dispersed systems t = 15 - 30 °C is proposed to be determined by the equations ρ(t) = 1001, 3 - 
0.00263t
2
- 0,1569t, μ (t) 
— 
0,0308t
-1,0259
3.
Experienced values for the solubility of magnetite for different values of temperature and 
hydrogen indicator pH of dispersed systems, for the temperature range of 15-30 ° C are recorded as a 
dependence,
C
m
(t, pH), kg/m3.
C
m
(t, pH)=
ρ
(mt
2
-nt+p)*10
-9
(8) 
where t, n, p - coefficients taken for different temperature ranges and pH values from the data 

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