A320-family/Systems/a320-apu.xml

<?xml version="1.0"?>

<!-- Airbus A320 APU -->
<!-- Copyright (c) 2020 Jonathan Redpath -->

<system name="A320: APU">

    <channel name="APU" execrate="8">
        <!-- bleed 1.8 kg / sec @ 42 psig -->
        <!-- fuel 148 kg/hr -->
		<!-- generator 24034 rpm, 10129 rpm fuel ctl, 32045 rpm starter, 51965 rpm cooling, 4137rpm oil pump -->

		<fcs_function name="/systems/apu/bleed-load-kw">
			<function>
				<ifthen>
					<eq>
						<property>/controls/pneumatics/switches/apu</property>
						<value>1</value>
					</eq>
					<value>252</value>
					<value>0</value>
				</ifthen>
			</function>
		</fcs_function>
		
		
		<fcs_function name="/systems/apu/electrical-load-kw">
			<function>
				<ifthen>
					<gt>
						<property>/systems/electrical/relay/apu-glc/output</property>
						<value>110</value>
					</gt>
					<value>132</value>
					<value>0</value>
				</ifthen>
			</function>
		</fcs_function>
		
		<fcs_function name="/systems/apu/apu-load-cmd">
			<function>
				<quotient>
					<sum>
						<property>/systems/apu/electrical-load-kw</property>
						<property>/systems/apu/bleed-load-kw</property>
					</sum>
					<value>400</value>
				</quotient>
			</function>
		</fcs_function>
		
		<actuator name="/systems/apu/apu-load">
			<input>/systems/apu/apu-load-cmd</input>
			<rate_limit>0.01</rate_limit> <!-- 60 seconds cooling period for bleed which is ~ 60% -->
		</actuator>
		
        <washout_filter name="/systems/apu/dn-dt">
            <input>/engines/engine[2]/n1</input>
            <c1>1</c1>
        </washout_filter>
        
        <fcs_function name="/systems/apu/egt-degC">
            <function>
				<sum>
					<product>
						<property>/systems/apu/apu-load</property>
						<value>50</value>
					</product>
					<ifthen>
						<or>
							<lt>
								<property>/engines/engine[2]/n1</property>
								<value>0.5</value>
							</lt>
							<gt>
								<property>/systems/apu/dn-dt</property>
								<value>0</value>
							</gt>
						</or>
						<table>
							<independentVar lookup="row">/engines/engine[2]/n1</independentVar>
							<tableData>
								5.0     20.0
								8.0     45.0
								10.0    120.0
								12.0    225.0
								18.0    430.0
								25.0    500.0
								27.0    560.0
								30.0    720.0
								35.0    785.0
								40.0    800.0
								45.0    795.0
								50.0    785.0
								60.0    755.0
								75.0    645.0
								90.0    520.0
								100.0   415.0
							</tableData>
						</table>
						<table>
							<independentVar lookup="row">/engines/engine[2]/n1</independentVar>
							<tableData>
								2.0     200.0
								8.0     220.0
								12.0    225.0
								18.0    240.0
								30.0    250.0
								50.0    265.0
								60.0    295.0
								75.0    380.0
								90.0    410.0
								100.0   415.0
							</tableData>
						</table>
					</ifthen>
				</sum>
            </function>
        </fcs_function>
        
        <fcs_function name="/systems/apu/oil/oil-pressure-psi">
            <function>
                <table>
                    <independentVar lookup="row">/engines/engine[2]/n1</independentVar>
                    <independentVar lookup="column">/systems/apu/oil/level-l</independentVar>
                    <tableData>
                              0   3.6   5.4
                        8     0   0     0
                        12    0   1     10
                        18    0   5     22
                        30    0   22    41
                        50    0   25    45
                        60    0   28    48
                        75    0   33    52
                        90    0   35    54
                        100   0   36    55
                    </tableData>
                </table>
            </function>
        </fcs_function>
		
		<fcs_function name="/systems/apu/oil/oil-temperature-degC">
            <function>
				<product>
					<sum>
						<value>1.0</value> <!-- tune -->
						<product>
							<property>/systems/apu/apu-load</property>
							<value>0.3</value>
						</product>
					</sum>
					<table>
						<independentVar lookup="row">/systems/apu/oil/oil-pressure-psi</independentVar>
						<tableData>
							0   0
							25  135
							35  105
							55  85
						</tableData>
					</table>
					<quotient>
						<property>/engines/engine[2]/n1</property>
						<value>100</value>
					</quotient>
				</product>
            </function>
        </fcs_function>
        
        <fcs_function name="/systems/apu/oil/calc-oil-level">
            <function>
                <sum>
                    <property>/systems/apu/oil/level-l</property>
                    <product>
						<quotient>
							<property>/engines/engine[2]/n1</property>
							<value>100</value>
						</quotient>
                        <property>/systems/apu/oil/allow-oil-consumption</property>
                        <value>-0.00000131437</value>
                        <property>simulation/channel-dt</property>
                    </product>
                </sum>
            </function>
            <output>/systems/apu/oil/level-l</output>
        </fcs_function>
    </channel>

</system>