Minenergo-325. Trace thermal-hydraulic regime for linear segment

Trace values of thermal-hydraulic regime (temperature, pressure, consumption) along the adjacent linear segments of pipeline using norms of heat flux values prescribed by Minenergo Order 325.

m325traceline(
  temperature = 130,
  pressure = mpa_kgf(6),
  consumption = 250,
  g = 0,
  d = 700,
  len = c(600, 530, 300, 350),
  year = 1986,
  insulation = 0,
  laying = "underground",
  beta = FALSE,
  exp5k = TRUE,
  roughness = 0.006,
  inlet = 0,
  outlet = 0,
  elev_tol = 0.1,
  method = "romeo",
  forward = TRUE,
  absg = TRUE
)

Arguments

temperature

temperature of heat carrier (water) inside the pipe sensor-measured at the inlet (forward tracing) or at the outlet (backward tracing) of path, [°C]. Type: assert_number.

pressure

absolute pressure of heat carrier (water) sensor-measured at the inlet (forward tracing) or at the outlet (backward tracing) of path, [MPa]. Type: assert_number.

consumption

amount of heat carrier (water) sensor-measured at the inlet (forward tracing) or at the outlet (backward tracing) of path, [ton/hour]. Type: assert_number.

g

amount of heat carrier discharge to network for each pipe segment in the tracing path enumerated along the direction of flow. If flag absg is TRUE then they treat argument g as absolute value in [ton/hour], otherwise they do as percentage of consumption in the pipe segment. Type: assert_double.

d

internal diameters of subsequent pipes in tracing path that are enumerated along the direction of flow, [mm]. Type: assert_double.

len

length of subsequent pipes in tracing path that are enumerated along the direction of flow, [m]. Type: assert_double.

year

year when pipe is put in operation after laying or total overhaul for each pipe in tracing path enumerated along the direction of flow. Type: assert_integerish.

insulation

insulation that covers the exterior of pipe:

0: no insulation
1: foamed polyurethane or analogue
2: polymer concrete

for each pipe in tracing path enumerated along the direction of flow. Type: assert_numeric and assert_subset.

laying

type of pipe laying depicting the position of pipe in space:

air
channel
room
tunnel
underground

for each pipe in tracing path enumerated along the direction of flow. Type: assert_character and assert_subset.

beta

should they consider additional heat losses of fittings? Logical value for each pipe in tracing path enumerated along the direction of flow. Type: assert_logical.

exp5k

pipe regime flag: is pipe operated more that 5000 hours per year? Logical value for each pipe in tracing path enumerated along the direction of flow. Type: assert_logical.

roughness

roughness of internal wall for each pipe in tracing path enumerated along the direction of flow, [m]. Type: assert_double.

inlet

elevation of pipe inlet for each pipe in tracing path enumerated along the direction of flow, [m]. Type: assert_double.

outlet

elevation of pipe outlet for each pipe in tracing path enumerated along the direction of flow, [m]. Type: assert_double.

elev_tol

maximum allowed discrepancy between adjacent outlet and inlet elevations of two subsequent pipes in the traced path, [m]. Type: assert_number.

method

method of determining Darcy friction factor

romeo
vatankhan
buzelli

Type: assert_choice. For more details see dropp.

forward

tracing direction flag: is it a forward direction of tracing? If FALSE the backward tracing is performed. Type: assert_flag.

absg

Whether argument g (amount of heat carrier discharge to network) is an absolute value in [ton/hour] (TRUE) or is it a percentage of consumption in the pipe segment (FALSE)? Type: assert_flag.

Value

named list of regime parameters for the traced path with the next elements:

temperature: calculated temperatures of heat carrier for all pipeline segments, [°C]. Type: assert_double.
pressure: calculated pressures of heat carrier for all pipeline segments, [MPa]. Type: assert_double.
consumption: calculated consumption(s) of heat carrier for all pipeline segments, [ton/hour]. Type: assert_double.

Details

The calculated (values of) regime may be considered as representation of district heating process in conditions of hypothetically perfect technical state of pipe walls and insulation.

They consider only simple tracing paths which do not contain rings and any kind of parallelization. At the same time bidirectional (forward and backward) tracing is possible in accordance with sensor position. They also may consider discharges to network at the inlet of each pipeline segment as an approximation of actual forks of flows. Relevant illustration of adopted assumptions for 4-segment tracing path is depicted on the next figure.

They make additional check for consistency of inlet and outlet values for subsequent pipe segments. Discrepancy of appropriate elevations cannot be more than elev_tol.

Examples

# Consider 4-segment tracing path depicted in ?m325regtrace help page.
# First, let sensor readings for forward tracing:
t_fw <- 130  # [°C]
p_fw <- .588399*all.equal(.588399, mpa_kgf(6))  # [MPa]
g_fw <- 250  # [ton/hour]

# Let discharges to network for each pipeline segment are somehow determined as
discharges <- seq(0, 30, 10)  # [ton/hour]

# \donttest{
# Then the calculated regime (red squares) for forward tracing is
regime_fw <- m325traceline(t_fw, p_fw, g_fw, discharges, forward = TRUE)
print(regime_fw)
#> $temperature
#> [1] 129.1799 128.4269 127.9628 127.3367
#> 
#> $pressure
#> [1] 0.5878607 0.5874226 0.5872143 0.5870330
#> 
#> $consumption
#> [1] 250 240 220 190
#> 

# $temperature
# [1] 129.1799 128.4269 127.9628 127.3367
#
# $pressure
# [1] 0.5878607 0.5874226 0.5872143 0.5870330
#
# $consumption
# [1] 250 240 220 190
# }
# Next consider values of traced regime as sensor readings for backward tracing:
t_bw <- 127.3367  # [°C]
p_bw <- .5870330  # [MPa]
g_bw <- 190  # [ton/hour]

# Then the calculated regime (red squares) for backward tracing is
# \donttest{
regime_bw <- m325traceline(t_bw, p_bw, g_bw, discharges, forward = FALSE)
print(regime_bw)
#> $temperature
#> [1] 129.9953 129.1769 128.4254 127.9619
#> 
#> $pressure
#> [1] 0.5883998 0.5878611 0.5874228 0.5872144
#> 
#> $consumption
#> [1] 250 250 240 220
#> 

# $temperature
# [1] 129.9953 129.1769 128.4254 127.9619
#
# $pressure
# [1] 0.5883998 0.5878611 0.5874228 0.5872144
#
# $consumption
# [1] 250 250 240 220

# Let compare sensor readings with backward tracing results:
tracing <- with(regime_bw, {
  lambda <- function(val, constraint)
    c(val, constraint, constraint - val,
      abs(constraint - val)*100/constraint)
  first <- 1
  structure(
    rbind(
      lambda(temperature[first], t_fw),
      lambda(pressure[first],    p_fw),
      lambda(consumption[first], g_fw)
    ),
    dimnames = list(
      c("temperature", "pressure", "consumption"),
      c("sensor.value", "traced.value", "abs.discr", "rel.discr")
    )
  )
})
print(tracing)
#>             sensor.value traced.value     abs.discr    rel.discr
#> temperature  129.9952943   130.000000  4.705723e-03 0.0036197868
#> pressure       0.5883998     0.588399 -8.290938e-07 0.0001409067
#> consumption  250.0000000   250.000000  0.000000e+00 0.0000000000

# sensor.value traced.value     abs.discr    rel.discr
# temperature   130.000000  129.9952943  4.705723e-03 0.0036197868
# pressure        0.588399    0.5883998 -8.290938e-07 0.0001409067
# consumption   250.000000  250.0000000  0.000000e+00 0.0000000000
# }

Minenergo-325. Trace thermal-hydraulic regime for linear segment

Arguments

Value

Details

See also

Examples