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Figure XXI. 2 Experimental setup for CO2 re-breathing validation There are two separate channels for exhalation phase flow and inhalation phase flow to guarantee the “exhaled” air has a consistent concentration of smoke. Besides the lung simulator, the CPAP and the mask, the components of the setup and their functions are listed below. Table XXI. 1 Components in CO2 re-breathing validation experimental setup and their functions Component Function Two flipper valves To direct the flow to the proper channel Smoke generating chamber To provide smoke Smoke mixing chamber To even smoke concentration Flow meters To check the breath load before measurement Stable light source To provide light to the photo-detectors Two photo-detectors Smoke filter To continuously record the smoke concentration in airflow For providing a stable smoke thickness for next breath cycle and for protecting the lung simulator cylinder The flow meters are used to check the breath load before the measurement is conducted. Since the exhalation phase channel is different from the inhalation channel, the inhalation phase breath load and the exhalation phase breath load should be separately adjusted. The light source and the photodetectors should have been calibrated before experiment is conducted. 270
The lung simulator drives the air. The two valves are controlled by the phase turning of the lung simulator which keeps in phase between the valves flipping and the lung simulator direction change. When exhalation phase starts, the valves close the inhalation channel and let the air only flows through the exhalation channel towards the mask (the upper part through the two chambers). The smoked air flows through the photodetector 1, the thickness (concentration) of the smoke will give reading in the photodetector 1 and be continuously recorded. When inhalation phase starts, the valves are flipped to close the exhalation channel and open the inhalation channel. The air flows through the photodetector 2, the thickness of the smoke (if any) will give reading in the photodetector 2 and also be continuously recorded. The calibrated reading from the photodetectors will be compared and the thickness (concentration) of the smoke in the inhaled air can be calculated. XXI.3 Validation of HADT condensation comparison between steady state and breathing-added situation As for the experimental validation of the HADT condensation, the setup can be designed as shown in Figure XXI. 3. However, the experiment has not been conducted due to instrument availability. Figure XXI. 3 Experimental setup for validation of HADT condensation with reverse flow The whole experiment is to validate the reverse flow’s influence on the HADT condensation. The purpose of this part of the setup shown above is to obtain an airflow mimicking the thermal properties of exhaled air. That is a 33°C~34°C and fully saturated airflow from the lung simulator to the mask. Ideally, there is another CPAP machine next to it running under steady flow for reference. 271
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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
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5.3.1.4 Airflow temperature at the
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flow rate had been even further inc
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Figure 5.31 Comparison of condensat
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Table 5.3 Comparison of condensatio
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3. The corrugated grooves on the HA
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5.3.2.1 Validation of evaporation r
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The experiment observation showed t
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Figure 6.1 Reverse flow under diffe
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It can also be seen in Figure 6.2 t
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within the same period. However, wh
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Figure 6.6 Comparison of evaporatio
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Figure 6.8 Airflow velocity in HADT
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Figure 6.11 Airflow velocity in HAD
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In Figure 6.14 the blue curve repre
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6.3.3.1.2 Comparison when heating e
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This vaporization potentiality (coi
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Figure 6.20 In-tube condensation of
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When using different sized masks, t
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Figure 6.23 Average specific humidi
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The average specific humidity in an
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Table 6.5 Comparison of average spe
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6. The deep breathing and reverse f
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Appendices Appendix I Regression of
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Appendix I. Regression of the press
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Figure I. 1 Tested results and the
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Appendix II. Regression of the pres
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Table III. 2 Airflow temperature an
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Appendix IV. The corrugated HADT ou
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The total area of the complicated c
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Figure V. 1 Regression of saturated
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This ratio can be regressed against
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Appendix VII. Details of the CPAP f
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VII.4 The mask pressure subsystem F
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Inputs to this water-centred subsys
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Input port number Input Unit 1 Heat
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input 4 is the portion of impact ar
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VIII.2.3 Water surface mass transfe
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This subsystem also contains two su
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VIII.2.5 Chamber wall 1 heat transf
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Figure VIII. 13 Wall 1 outer surfac
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Wall 2 and 3 inner surface temperat
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Figure VIII. 17 Chamber wall 2 and
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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
Page 265 and 266: Figure XI. 4 Steady state mask wall
Page 267 and 268: Input port number Input Unit 1 Aver
Page 269 and 270: Appendix XII. Details of mask air d
Page 271 and 272: 4 Length of the triangular plate in
Page 273 and 274: 8 Length of the triangular plate in
Page 275 and 276: Appendix XIII. Details of the auxil
Page 277 and 278: XIII.3 Breath load average subsyste
Page 279 and 280: Figure XIII. 7 Average evaporation
Page 281 and 282: XIV.1.2 Under normal ambient temper
Page 283 and 284: XIV.2.3 Under high ambient temperat
Page 285 and 286: XIV.4 Airflow temperature at the en
Page 287 and 288: XIV.5.2 Under normal ambient temper
Page 289 and 290: XIV.6.3 Under high ambient temperat
Page 291 and 292: Appendix XVI. Regression of kinetic
Page 293 and 294: Figure XVII. 2 Condensation/evapora
Page 295 and 296: Figure XVIII. 2 Condensation/evapor
Page 297 and 298: at point C. Right after that, here
Page 299 and 300: Appendix XIX. Coefficient and param
Page 301 and 302: Average water thermal conductivity
Page 303: Appendix XXI. Fluid dynamic and the
Page 307 and 308: Appendix XXII. Model user instructi
Page 309 and 310: The input blocks and their values a
Page 311 and 312: Dynamically fluctuating air tempera
Page 313 and 314: References [1] Good sleep advice. W
Page 315 and 316: [28] Schettino GPP, Chatmongkolchar
Page 317: [60] Marek R, Straub J. Analysis of
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