def headloss(req, roughness, internal_dimension):
"""Calculate velocity and headloss for selected dimension.
:param req: request.get_json() flask's method to get json from user
:param roughness: roughness of pipe in [mm]
:param internal_dimension: internal dimension of pipe depends on nominal diameter
"""
density = req['density']
viscosity = req['viscosity']
# pipe
area = circular_pipe(internal_dimension, 'mm')
length = req['length']
llc = req.get('local_loss_coefficient', 0)
# flow
velocity = velocity_equation(req['flow'], req['flow_unit'], area)
reynolds = reynolds_equation(velocity, internal_dimension, viscosity)
# headloss
headloss_unit = req.get('headloss_unit', 'Pa')
dfc = darcy_friction_coefficient(reynolds, internal_dimension, roughness)
loss = darcy_weisbach_equation(
dfc, llc, length, unit_convertion(internal_dimension, 'mm', 'm', 'lenght'), density, velocity
)
return api_response(
{
'velocity': velocity,
'velocity_unit': 'm/s',
'headloss': unit_convertion(loss, 'Pa', headloss_unit, 'pressure'),
'headloss_unit': headloss_unit,
}
)
def velocity_equation(flow, flow_unit, area):
"""Calculate average velocity.
:param flow: volume flow rate
:param flow_unit: flow unit e.g.: [m3/h], [m3/s]
:param area: area of pipe's cross section [m2]"""
try:
volume_unit, time_unit = flow_unit.split('/')
volume_convertion = unit_convertion(1, volume_unit, 'm3', 'volume')
time_convertion = unit_convertion(1, time_unit, 's', 'time')
return round_units((flow * volume_convertion / time_convertion) / area,
3)
except (ValueError, TypeError):
return 'Wrong volume flow rate!'
def circular_pipe(diameter, unit):
"""Circular area in [m2].
:param diameter: value of internal diameter
:param unit: unit of diameter e.g.: [mm] or [m]
"""
converted_diameter = unit_convertion(diameter, unit, 'm', 'lenght')
return round(math.pow(converted_diameter, 2) * math.pi / 4, 10)
def rectangular_dict(width, height, unit):
"""Rectangular area in [m2].
:param width: duct width (A - dimension)
:param height: duct height (B - dimension)
:param unit: unit od dimensions e.g.: [mm] or [m]
"""
conversion_value = math.pow(unit_convertion(1, unit, 'm', 'lenght'), 2)
return round(width * height * conversion_value, 10)
def wrapper(req, *args, **kwargs):
if 'power' in req:
power = unit_convertion(req['power'], req['power_unit'], 'W',
'power')
temperature_delta = abs(req['temperature_supply'] -
req['temperature_return'])
if not temperature_delta:
return error_response(
400,
'Temperature supply and return can not have the same value.'
)
flow = power / (temperature_delta * req['density'] *
req['specific_heat'])
req.update({'flow': flow, 'flow_unit': 'm3/s'})
return func(*args, req=req, **kwargs)
def selecting_optimum_pipe_size(req):
"""Calculate velocity and headloss for every dimension.
:param req: request.get_json() flask's method to get json from user
"""
density = req['density']
viscosity = req['viscosity']
roughness = req.get('roughness', 1.5)
results = []
for nominal_diameter, internal_dimension in get_internal_diameters(req['material']):
area = circular_pipe(internal_dimension, 'mm')
velocity = velocity_equation(req['flow'], req['flow_unit'], area)
reynolds = reynolds_equation(velocity, internal_dimension, viscosity)
dfc = darcy_friction_coefficient(reynolds, internal_dimension, roughness)
loss = darcy_weisbach_equation(
dfc, 0, 1, unit_convertion(internal_dimension, 'mm', 'm', 'lenght'), density, velocity
)
results.append({'nominal_diameter': nominal_diameter, 'headloss': loss, 'velocity': velocity})
return api_response({'headloss_unit': 'Pa/m', 'velocity_unit': 'm/s', 'results': results})
def test_unit_convertion_failed(value, unit_from, unit_to, data_type, expected_message):
assert unit_convertion(value, unit_from, unit_to, data_type) == expected_message
def test_unit_convertion(value, unit_from, unit_to, data_type, expected_value):
assert unit_convertion(value, unit_from, unit_to, data_type) == expected_value