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4.3.1 Thermal section of ADU and chamber part The ADU and chamber part is created based on sections 3.2, 3.3 and 3.4, chapter 3. This part is the most complicated. There are two main subsystems in this part. One is whole chamber steady state subsystem and another is the dynamic chamber-air thermal balance subsystem. The whole chamber steady state subsystem is mainly to provide the water temperature to be used by chamber-air subsystem. The dynamic chamber-air subsystem is for obtaining dynamic fluctuating air flow velocity, chamber air temperature and specific humidity. The air flow velocity, airflow temperature and humidity are properties of the airflow provided to the patient through the long HADT and the mask. These properties will be key factors for the analysis and comparison of condensation in the HADT and the mask. Details in these two subsystems will be shown and described later. The inputs are listed in Table 4.13 below. Input port number 1 Table 4.13 Inputs to the thermal section of ADU and chamber part Input Unit Specific humidity of air from HADT due to reverse flow 92 In decimal 2 Temperature of air from HADT due to reverse flow °C 3 Breath load g/s 4 Heat element temperature setting °C 5 CPAP pressure setting cmH2O 6 Ambient air temperature °C 7 Ambient air specific humidity In decimal 8 Mask capacity m 3
The outputs are listed in Table 4.14 below. output port number Figure 4.14 ADU and chamber part subsystem Table 4.14 Outputs from the thermal section of ADU and chamber part output Unit 1 Fluctuating specific humidity in the chamber In decimal 2 Fluctuating air temperature in the chamber °C 3 Fluctuating airflow velocity in HADT m/s 4 Fluctuating evaporation rate kg/s 5 Water temperature °C 93
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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
Page 75 and 76: Figure 3.6 Heating element beneath
Page 77 and 78: Figure 3.8 Chamber water heat balan
Page 79 and 80: Table 3.1 Thermal resistance from h
Page 81 and 82: 3.3.1.2 Heat balance at the outer s
Page 83 and 84: 3.3.2 Heat flow from chamber water
Page 85 and 86: through ADU which is a function of
Page 87 and 88: It is assumed that the direct impac
Page 89 and 90: Sc a a (3.47) Dwa Analogous to th
Page 91 and 92: and keep them in gaseous status. On
Page 93 and 94: through the walls and natural conve
Page 95 and 96: Where d Ca is the specific humidity
Page 97 and 98: TTa ( n1) is also considered as inl
Page 99 and 100: R Torn 2 2 ATlor ( TTWn T )( TTWn
Page 101 and 102: condensation severity but cannot ca
Page 103 and 104: condensation has occurred at all or
Page 105 and 106: The inlet is the air from HADT duri
Page 107 and 108: 3.9 Average temperature of inhaled
Page 109 and 110: Table 4.1 Inputs to the fluid dynam
Page 111 and 112: Figure 4.2 Simulink TM model for fl
Page 113 and 114: Table 4.4 Outputs from the overall
Page 115 and 116: Gain block after input 1 is to conv
Page 117 and 118: Figure 4.7 Varying Transport Delay
Page 119 and 120: 4.2.5 Mask mixing calculation subsy
Page 121 and 122: 4.3 Computational model of thermal
Page 123 and 124: Figure 4.11 Block diagram of CPAP t
Page 125: Figure 4.13 Simulink TM model for t
Page 129 and 130: The outputs are listed in Table 4.1
Page 131 and 132: Figure 4.16 Dynamic chamber-air the
Page 133 and 134: Figure 4.17 HADT lump thermal balan
Page 135 and 136: Figure 4.18 Steady state HADT lump
Page 137 and 138: Figure 4.19 HADT lump air dynamic f
Page 139 and 140: The outputs are listed in Table 4.2
Page 141 and 142: Figure 4.21Steady state mask full t
Page 143 and 144: 4 Temperature of airflow from HADT
Page 145 and 146: Average evaporation rate subsystem
Page 147 and 148: HADT and connects those upstream se
Page 149 and 150: The experiment was also carried out
Page 151 and 152: air flowing through the elbow, a ce
Page 153 and 154: expansion from the elbow to the mas
Page 155 and 156: Figure 5.12 Environmental control r
Page 157 and 158: Table 5.1 shows the combinations of
Page 159 and 160: Figure 5.17 Comparison of model out
Page 161 and 162: The comparison of experimental resu
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
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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
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Appendix IX. Details of steady stat
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Figure IX. 3 The HADT lump wall out
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Appendix X. Details of HADT lump ai
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2 Absolute value of airflow velocit
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Figure X. 5 HADT lump inlet absolut
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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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