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0.08 0 407.32 0 407.32 15.81 0.91 408.9 0.48 409.38 31.22 1.8 409.33 1.86 411.19 45.44 2.62 395.43 3.94 399.37 60.67 3.49 369.65 7.02 376.67 74.81 4.31 335.84 10.67 346.51 89.77 5.17 291.29 15.36 306.65 97.75 5.63 264.59 18.22 282.81 Q(L/min) V(m/s) Table I. 2 Second round of ADU outlet pressure P_Measured (static) (Pa) - 180 - P Compensate (Pa) P_stag(Pa) -30.77 -1.77 450 1.81 451.81 -21.36 -1.23 435.82 0.88 436.7 -9.87 -0.57 421.75 0.19 421.94 0.06 0 406.5 0 406.5 14.44 0.83 408.84 0.4 409.24 29.5 1.7 411.44 1.66 413.1 44.74 2.58 394.71 3.82 398.53 59.57 3.43 371.94 6.77 378.71 74.56 4.29 337.22 10.6 347.82 88.36 5.09 296.6 14.88 311.48 97.26 5.6 267.33 18.04 285.37 By using curve fitting and averaging of the two rounds, the relationship of ADU outlet pressure vs. airflow velocity in the duct can be expressed as: P u u u 3 2 Ao 1.1387 D 3.2879 D 10.0609 D 415.40 The tested results and the regressed curve is shown in figure below:
Figure I. 1 Tested results and the regressed curve for ADU outlet pressure when pressure setting is 4cmH2O By using the same method, such a 3-ordered expression can be obtained for each of the tested pressure settings. The coefficients for each pressure setting are listed below: P Ao a b c d 4cmH2O -1.1387 3.2879 -10.0609 415.40 6cmH2O -1.1219 3.8749 -9.4252 611.44 8cmH2O -1.3316 5.8853 -10.4933 807.36 10cmH2O -1.4676 7.2633 -9.4144 1001.50 12cmH2O -1.6729 9.3706 -11.9589 1187.60 14cmH2O -1.8456 10.7920 -10.7130 1378.05 16cmH2O -2.1916 14.0150 -14.9430 1563.70 18cmH2O -2.4434 15.5360 -9.6832 1748.35 20cmH2O -2.5066 16.9690 -12.4421 1957.05 It is convenient for dynamic simulation modelling to unify them by regressing the coefficients again as: a 0.0961P 0.5932 i set b 0.9124P 1.2827 i set c 0.1791P 8.9763 i set - 181 -
Page 1 and 2:
The Effects of CPAP Tube Reverse Fl
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Acknowledgement First of all, I wou
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When deep breathing induced reverse
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2.4.1 Reverse flow calculation ....
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5.3.1 Thermal dynamic model under s
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XI.3 Steady state mask thermal bala
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List of Figures Figure 1.1 Obstruct
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Figure 5.10 Comparison between expe
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Figure 6.13 Fluctuation of airflow
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Table 5.3 Comparison of condensatio
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Nomenclature Symbol Meaning of the
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CMFeO CMFet C O C t Concentration o
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m C 23 m Ca m cv m Cw m store m i m
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Nu Cp Nu dir Nu Ti Nu To Nuwsn Nuws
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QMor QMwst QTastn QTicn QTin Q
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R Mic R Moc R Ticn R Toc R Torn Mas
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V Capacity of the container m 3 V C
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1.1 Background Chapter 1 Introducti
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The MRD is worn in user’s mouth w
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Figure 1.4 CPAP machine Figure 1.5
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1.3 Literature survey A literature
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CPAP fluid dynamic performance with
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Chapter 2 Mathematical Modelling of
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2.3 Fluid dynamic analysis This sec
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If there are minor pressure drops,
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Figure 2.6 Pressure sensor - Honeyw
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The pressure readings were taken af
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Figure 2.12 Experimental set up for
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2.3.4 Chamber air space mass balanc
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From the above analysis, the pressu
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Figure 2.18 Full face mask and the
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Inserting Eq. (2.26) and Eq. (2.27)
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Where n( ) t is the airflow proper
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However in reality, mixing turns ou
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Chapter 3 Mathematical Modelling of
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An Environment Control Chamber (Vö
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Figure 3.4 Thermal enthalpy gain of
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Figure 3.6 Heating element beneath
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Figure 3.8 Chamber water heat balan
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Table 3.1 Thermal resistance from h
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3.3.1.2 Heat balance at the outer s
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3.3.2 Heat flow from chamber water
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through ADU which is a function of
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It is assumed that the direct impac
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Sc a a (3.47) Dwa Analogous to th
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and keep them in gaseous status. On
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through the walls and natural conve
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Where d Ca is the specific humidity
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TTa ( n1) is also considered as inl
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R Torn 2 2 ATlor ( TTWn T )( TTWn
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condensation severity but cannot ca
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condensation has occurred at all or
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The inlet is the air from HADT duri
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3.9 Average temperature of inhaled
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Table 4.1 Inputs to the fluid dynam
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Figure 4.2 Simulink TM model for fl
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Table 4.4 Outputs from the overall
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Gain block after input 1 is to conv
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Figure 4.7 Varying Transport Delay
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4.2.5 Mask mixing calculation subsy
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4.3 Computational model of thermal
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Figure 4.11 Block diagram of CPAP t
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Figure 4.13 Simulink TM model for t
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The outputs are listed in Table 4.1
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Figure 4.16 Dynamic chamber-air the
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Figure 4.17 HADT lump thermal balan
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Figure 4.18 Steady state HADT lump
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Figure 4.19 HADT lump air dynamic f
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Figure 4.21Steady state mask full t
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4 Temperature of airflow from HADT
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Average evaporation rate subsystem
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HADT and connects those upstream se
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The experiment was also carried out
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air flowing through the elbow, a ce
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expansion from the elbow to the mas
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Figure 5.12 Environmental control r
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Table 5.1 shows the combinations of
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Figure 5.17 Comparison of model out
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The comparison of experimental resu
Page 163 and 164: Figure 5.22 Comparison of model out
Page 165 and 166: Figure 5.24 Comparison of model out
Page 167 and 168: 5.3.1.4 Airflow temperature at the
Page 169 and 170: flow rate had been even further inc
Page 171 and 172: Figure 5.31 Comparison of condensat
Page 173 and 174: Table 5.3 Comparison of condensatio
Page 175 and 176: 3. The corrugated grooves on the HA
Page 177 and 178: 5.3.2.1 Validation of evaporation r
Page 179 and 180: The experiment observation showed t
Page 181 and 182: Figure 6.1 Reverse flow under diffe
Page 183 and 184: It can also be seen in Figure 6.2 t
Page 185 and 186: within the same period. However, wh
Page 187 and 188: Figure 6.6 Comparison of evaporatio
Page 189 and 190: Figure 6.8 Airflow velocity in HADT
Page 191 and 192: Figure 6.11 Airflow velocity in HAD
Page 193 and 194: In Figure 6.14 the blue curve repre
Page 195 and 196: 6.3.3.1.2 Comparison when heating e
Page 197 and 198: This vaporization potentiality (coi
Page 199 and 200: Figure 6.20 In-tube condensation of
Page 201 and 202: When using different sized masks, t
Page 203 and 204: Figure 6.23 Average specific humidi
Page 205 and 206: The average specific humidity in an
Page 207 and 208: Table 6.5 Comparison of average spe
Page 209 and 210: 6. The deep breathing and reverse f
Page 211 and 212: Appendices Appendix I Regression of
Page 213: Appendix I. Regression of the press
Page 217 and 218: Appendix II. Regression of the pres
Page 219 and 220: Table III. 2 Airflow temperature an
Page 221 and 222: Appendix IV. The corrugated HADT ou
Page 223 and 224: The total area of the complicated c
Page 225 and 226: Figure V. 1 Regression of saturated
Page 227 and 228: This ratio can be regressed against
Page 229 and 230: Appendix VII. Details of the CPAP f
Page 231 and 232: VII.4 The mask pressure subsystem F
Page 233 and 234: Inputs to this water-centred subsys
Page 235 and 236: Input port number Input Unit 1 Heat
Page 237 and 238: input 4 is the portion of impact ar
Page 239 and 240: VIII.2.3 Water surface mass transfe
Page 241 and 242: This subsystem also contains two su
Page 243 and 244: VIII.2.5 Chamber wall 1 heat transf
Page 245 and 246: Figure VIII. 13 Wall 1 outer surfac
Page 247 and 248: Wall 2 and 3 inner surface temperat
Page 249 and 250: Figure VIII. 17 Chamber wall 2 and
Page 251 and 252: Inputs to this subsystem are listed
Page 253 and 254: Appendix IX. Details of steady stat
Page 255 and 256: Figure IX. 3 The HADT lump wall out
Page 257 and 258: Appendix X. Details of HADT lump ai
Page 259 and 260: 2 Absolute value of airflow velocit
Page 261 and 262: Figure X. 5 HADT lump inlet absolut
Page 263 and 264: Figure XI. 2 Steady state mask mixi
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Figure XI. 4 Steady state mask wall
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Input port number Input Unit 1 Aver
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Appendix XII. Details of mask air d
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4 Length of the triangular plate in
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8 Length of the triangular plate in
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Appendix XIII. Details of the auxil
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XIII.3 Breath load average subsyste
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Figure XIII. 7 Average evaporation
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XIV.1.2 Under normal ambient temper
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XIV.2.3 Under high ambient temperat
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XIV.4 Airflow temperature at the en
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XIV.5.2 Under normal ambient temper
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XIV.6.3 Under high ambient temperat
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Appendix XVI. Regression of kinetic
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Figure XVII. 2 Condensation/evapora
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Figure XVIII. 2 Condensation/evapor
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at point C. Right after that, here
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Appendix XIX. Coefficient and param
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Average water thermal conductivity
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Appendix XXI. Fluid dynamic and the
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The lung simulator drives the air.
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Appendix XXII. Model user instructi
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The input blocks and their values a
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Dynamically fluctuating air tempera
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References [1] Good sleep advice. W
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[28] Schettino GPP, Chatmongkolchar
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[60] Marek R, Straub J. Analysis of
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