304 lines
11 KiB
Python
304 lines
11 KiB
Python
"""Compute various values for THE Henry Pump."""
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from math import sqrt
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import matplotlib.pyplot as plt
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# GLOBAL PARAMETERS
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g_dt = 0.050 # seconds
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g_thread_pitch = 0.5906
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g_accel_time = 1.0 # seconds
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g_decel_time = 1.0 # seconds
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g_stroke_length = 60.0 # inches
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g_upper_offset = 9.0 # inches
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g_lower_offset = 16.0 # inches
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g_motor_full_speed_hz = 120.0 # Hz
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g_motor_full_speed_rpm = 1200.0 # RPM
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g_run_speed = 120.0 # Hz
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MAX_NUT_ENDLOAD = 11000.0 # pounds
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FLUID_GRADIENT = 0.43733 # PSI/ft
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pump_constants = {
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0.625: 0.046,
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0.75: 0.066,
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0.9375: 0.117,
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1.0625: 0.132,
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1.125: 0.148,
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1.25: 0.182,
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1.5: 0.262,
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1.75: 0.357,
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1.78125: 0.370,
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2.0: 0.466,
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2.25: 0.590,
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2.5: 0.728,
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2.75: 0.861,
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3.75: 1.640,
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4.75: 2.630
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}
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fluid_load_constants = {
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1.0625: 0.384,
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1.25: 0.531,
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1.5: 0.765,
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1.75: 1.041,
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2.0: 1.36,
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2.25: 1.721,
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2.5: 2.125,
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2.75: 2.571
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}
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def _ftlb_to_nm(ftlb):
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"""Convert ft-lbs to n-m."""
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return ftlb / 0.73756
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def _nm_to_ftlb(nm):
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"""Convert n-m to ft-lbs."""
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return nm * 0.73756
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def max_production(pump_size, strokes_per_minute, stroke_length):
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"""Calculate the maximum production capabilities of a pump at a speed."""
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try:
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return pump_constants[pump_size] * strokes_per_minute * stroke_length
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except KeyError:
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print("No pump constant for that size pump.")
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def end_load(pump_size, depth, strokes_per_minute, stroke_length):
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"""Calculate the end load on the nut."""
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try:
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fluid_load_constant = fluid_load_constants[pump_size]
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return depth * fluid_load_constant * (FLUID_GRADIENT / 0.433)
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except KeyError:
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print("No fluid load constant for that size pump.")
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def max_producing_depth(pump_size):
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"""Calculate the maximum producing depth."""
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try:
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fluid_load_constant = fluid_load_constants[pump_size]
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return MAX_NUT_ENDLOAD / (fluid_load_constant * (FLUID_GRADIENT / 0.433))
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except KeyError:
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print("No fluid load constant for that size pump.")
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def voltage_drop(length, current, temperature, circular_mils, alpha):
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"""Calculate the voltage drop in the wire."""
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k20 = 10.37 # 1.26 / 1000.0 # ohms of 1 circular mil foot of conductor
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return sqrt(3) * k20 * (1.0 + alpha * ((5.0 / 9.0) * (temperature - 32.0) - 20.0)) * length * current / circular_mils
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def calc_voltage_needed(input_voltage, voltage_drop):
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"""Calculate the voltage needed given an input voltage and a voltage drop."""
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return input_voltage + voltage_drop
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def print_voltage_drops():
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"""Print values for voltage drop at distances."""
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current = 10.4 # Amps
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temperature = 250.0 # degress F
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circular_mils = 10384.0 # cross-sectional area in circular mils of conductor
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alpha_copper = 0.00393
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motor_input_voltage = 380.0
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print("---")
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for x in [400.0, 1000.0, 2000.0, 3000.0, 4000.0, 5000.0, 6000.0, 7000.0, 8000.0, 9000.0, 10000.0]:
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v_dropped = voltage_drop(x, current, temperature, circular_mils, alpha_copper)
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v_output = calc_voltage_needed(motor_input_voltage, v_dropped)
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print("Length: {}".format(x))
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print("Voltage Drop: {} V".format(round(v_dropped, 3)))
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print("Output Voltage: {} V".format(round(v_output, 3)))
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print("Motor Input Voltage {} V".format(round(motor_input_voltage, 3)))
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print("---")
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def time_for_freq_change(freq_delta, np_hz, ramp_time):
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"""Calculate the time required for a frequency change."""
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return (freq_delta / np_hz) * ramp_time
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def dist_for_freq_change(freq_delta, ramp_time, np_hz, np_rpm, thread_pitch):
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"""Calculate the distance required for a frequency change."""
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time_required = time_for_freq_change(freq_delta, np_hz, ramp_time)
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return 0.5 * time_required * freq_delta * (np_rpm / np_hz) * (1.0 / 60.0) * thread_pitch
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def time_for_uniform_freq(freq, distance, np_hz, np_rpm, thread_pitch):
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"""Calculate the time required to move a distance at a constant frequency."""
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return distance / (freq * (np_rpm / np_hz) * (1.0 / 60.0) * thread_pitch)
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def calculate_stroke_time(stroke_length, upper_offset, lower_offset, run_frequency, accel_time, decel_time, nameplate_hz=120.0, nameplate_rpm=1200.0, thread_pitch=0.5406):
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"""Calculate the time it takes to make a full stroke."""
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ramp_up_time = time_for_freq_change(run_frequency, nameplate_hz, accel_time)
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ramp_up_dist = dist_for_freq_change(run_frequency, accel_time, nameplate_hz, nameplate_rpm, thread_pitch)
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ramp_down_time = time_for_freq_change(run_frequency, nameplate_hz, decel_time)
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ramp_down_dist = dist_for_freq_change(run_frequency, decel_time, nameplate_hz, nameplate_rpm, thread_pitch)
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run_dist = stroke_length - (lower_offset + upper_offset + ramp_up_dist + ramp_down_dist)
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run_time = time_for_uniform_freq(run_frequency, run_dist, nameplate_hz, nameplate_rpm, thread_pitch)
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stroke_time = 2.0 * (ramp_up_time + run_time + ramp_down_time)
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return stroke_time
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def print_stroke_times():
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"""Print the required frequency for different SPM's with different ramp times."""
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for ramp_i in [0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0]:
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print("-----")
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print("Ramp Rate: {}".format(ramp_i))
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for hz_i in [20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0, 100.0, 110.0, 120.0]:
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spm = 60 / calculate_stroke_time(g_stroke_length, g_upper_offset, g_lower_offset, hz_i, ramp_i, ramp_i)
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print("Freq: {} Hz., SPM: {}".format(hz_i, spm))
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def sim(run_freq, dt, num_strokes, stroke_length, accel_time, decel_time, upper_offset, lower_offset, motor_full_speed_hz, motor_full_speed_rpm, thread_pitch, use_average=False):
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"""Run the main simulation loop."""
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strokes = 0
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time_to_turnaround = time_for_freq_change(run_freq, motor_full_speed_hz, decel_time)
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# time_to_turnaround = decel_time - (motor_full_speed_hz - run_freq) * decel_time / motor_full_speed_hz
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print("Turn Time: {} s.".format(time_to_turnaround))
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distance_to_turnaround = dist_for_freq_change(run_freq, decel_time, motor_full_speed_hz, motor_full_speed_rpm, thread_pitch)
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# distance_to_turnaround = 0.5 * time_to_turnaround * run_freq * (motor_full_speed_rpm / motor_full_speed_hz) * (1.0 / 60.0) * thread_pitch
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print("Turn Distance: {} in.".format(distance_to_turnaround))
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upper_turnaround_target = stroke_length - (upper_offset + distance_to_turnaround)
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upper_offset_target = stroke_length - upper_offset
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lower_turnaround_target = lower_offset + distance_to_turnaround
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print("--")
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print("Targets")
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print("-")
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print("Lower Offset: {} in.".format(lower_offset))
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print("Turnaround Target: {} in.".format(upper_turnaround_target))
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print("Upper Offset: {} in.".format(upper_offset_target))
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print("Lower Turnaround Target: {} in.".format(lower_turnaround_target))
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print("--")
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position = lower_offset
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time = 0.0
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direction = 1
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starting_speed = 0.0 # Hz
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speed = starting_speed
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last_speed = speed
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speed_array = []
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position_array = []
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time_array = []
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stroke_part = -1
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max_position = 0
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min_position = stroke_length
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while strokes != num_strokes:
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last_speed = speed
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if direction == 1:
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if position < upper_turnaround_target:
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# below offset and turnaround, ramp up to setpoint, then run at setpoint
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if stroke_part != 0:
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stroke_part = 0
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print("{} - {}".format(stroke_part, position))
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if speed < run_freq:
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speed += (motor_full_speed_hz / accel_time) * dt
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if speed > run_freq:
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speed = run_freq
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elif position >= upper_turnaround_target:
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# above turnaround distance, ramp to 0 and change direction
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if stroke_part != 1:
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stroke_part = 1
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print("{} - {}".format(stroke_part, position))
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if speed > 0:
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speed += -1.0 * (motor_full_speed_hz / decel_time) * dt
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if speed <= 0:
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speed = 0
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direction = -1
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elif direction == -1:
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if position > lower_turnaround_target:
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# above offset and rampdown distance, ramp up to setpoint (negative), then run at setpoint
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if stroke_part != 2:
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stroke_part = 2
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print("{} - {}".format(stroke_part, position))
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if speed > (-1.0 * run_freq):
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speed += -1.0 * (motor_full_speed_hz / accel_time) * dt
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if speed < (-1.0 * run_freq):
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speed = -1.0 * run_freq
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elif position <= lower_turnaround_target:
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# below turnaround distance, ramp to 0 and change direction
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if stroke_part != 3:
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stroke_part = 3
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print("{} - {}".format(stroke_part, position))
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if speed < 0:
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speed += 1.0 * (motor_full_speed_hz / decel_time) * dt
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if speed >= 0:
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speed = 0
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direction = 1
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strokes += 1
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if use_average:
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delta_x = (speed + last_speed) / 2.0 * (motor_full_speed_rpm / motor_full_speed_hz) * (dt / 60.0) * thread_pitch
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else:
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delta_x = speed * (motor_full_speed_rpm / motor_full_speed_hz) * (dt / 60.0) * thread_pitch
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position += delta_x
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time += dt
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speed_array.append(speed * (motor_full_speed_rpm / motor_full_speed_hz))
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position_array.append(position)
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time_array.append(time)
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# print("Time: {} sec., Position: {} in., Speed: {}".format(time, position, speed * (motor_full_speed_rpm / motor_full_speed_hz)))
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# sleep(dt)
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if stroke_part == 1:
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max_position = max([max_position, position])
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if stroke_part == 3:
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min_position = min([min_position, position])
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SPM = 60.0 / (time / strokes)
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# max_position = max(position_array)
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# min_position = min(position_array)
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print("Max: {}, Min: {}".format(max_position, min_position))
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print("SPM: {}".format(SPM))
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fig, ax1 = plt.subplots()
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ax1.plot(time_array, speed_array, "b-", linewidth=2)
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# ax1.plot(position_array, speed_array, "b-", linewidth=2)
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ax1.set_ylabel("RPM", color="b")
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ax2 = ax1.twinx()
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ax2.plot(time_array, position_array, "r-", linewidth=2)
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ax2.set_ylabel("in.", color="r")
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fig.tight_layout()
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ax1.grid(color='black', linestyle='--', linewidth=1)
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plt.show()
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def calc_travel_time(distance, speed_rpm, thread_pitch):
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"""Calculate the time it takes to travel a distatnce at a speed."""
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rotations_needed = distance / thread_pitch
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minutes_for_full_travel = rotations_needed / speed_rpm
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seconds_for_full_travel = minutes_for_full_travel / 60.0
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return seconds_for_full_travel
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def calc_theoretical_production(stroke_length, spm, pump_diameter):
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"""Calculate the maximum production for a given stroke length and speed."""
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try:
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return stroke_length * pump_constants[pump_diameter] * spm
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except IndexError:
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print("Cannot find pump constant for that diameter.")
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return False
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if __name__ == '__main__':
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sim(g_run_speed, g_dt, 5, g_stroke_length, g_accel_time, g_decel_time, g_upper_offset,
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g_lower_offset, g_motor_full_speed_hz, g_motor_full_speed_rpm, g_thread_pitch, use_average=False)
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