Specifications - DeeEmm/DIY-Flow-Bench GitHub Wiki
The DIYFB project has been developed to provide a fully featured flow bench that is comparable with modern commercial benches. Our overall goal is to match and exceed current industry standards.
The list below outlines the specifications and current feature set
Measurement Units
Mass Flow
- KGH - Kilogram per hour
Volumetric Flow
- CFM - Cubic Feet Per minute
Velocity
- M/Sec - Metres per second
Differential / Depression
- inH2O - Inches of Water
Temperature
- Degrees Celcius
- Degrees Farenheit
Barometric Pressure
- Millibar (hPa) - Millibar / Hecto Pascal
Humidity
- %RelH - Percent Relative Humidity
Supported Measurement Standards
- ISO 1585 (25°C(68°F) 100kPa 0%RH)
- ISO 5011 (20°C(68°F) 1atm(101.3kPa) 50%RH)
- ISA (15°C(59°F) 1atm(101.325kPa) 0%RH)
- ISO 13443 (15°C(59°F) 1atm(101.325kPa) 0%RH)
- ISO 2533 (15°C(59°F) 1atm(101.325kPa) 0% RH)
Control Schemas
Mass Flow
- KGH - Derived from MAF sensor transfer function
Volumetric Flow
- ACFM - [Actual CFM] Calculated from Mass flow (KGH) at current Baro, Temp and Humidity (from BME280)
- ACFM @ pRef - ACFM transposed for specified pRef (Depression in CFM). NOTE: Can be used for variable depression measurement
- SCFM - [Standard CFM] - ACFM transposed for specified standard reference conditions
Environmental Compensation
Temperature
- Degrees Celcius
- Degrees Farenheit
Barometric Pressure
- Millibar (hPa) - Millibar / Hecto Pascal
Humidity
- %RelH - Percent Relative Humidity
Calibration Schema
Reference Orifice Offset
Leak Test Offset
Baseline Offset
Integrated Tools
Pitot measurement - Velocity in m/sec
Flow Differential - User definable flow targets
Performance Specifications
- Max Flow - Defined by type of MAF sensor (1805 kg/h for BOSCH 0280218067 - approx 822 cfm under standard ref conditions)
- Max Reference Depression - Defined by type of Reference sensor (pRef) - Recommended +/- 7kPa pRef sensor to give 28 inH2O range
- Reference Depression Resolution - 0.000061v/bit = 0.000854kpa resolution for Recommended +/- 7kPa pRef sensor
- MAF Flow Resolution - Defined by type of MAF sensor - 0.000061v/bit = 0.013 cfm resolution for BOSCH 0280218067 MAF sensor
- General Accuracy - 0.1 cfm (calculated for BOSCH 0280218067 MAF)
Note: Performance specifications are influenced by the choice of components used. Using a reference pressure sensor that has a larger range than required will lower the resolution and accuracy of the system. Similarly, selecting a MAF sensor that has a maximum flow many times larger than you will typically measure will also lower the resolution and accuracy of your system.
The accuracy and resolution of the system can be improved by selecting MAF and pRef sensors closer to the range that you would generally measure.