§1065.640. Flow meter calibration calculations. — Inbound Citations

(6) We recommend that you connect multiple exhaust stacks from a single engine into one stack upstream of any emission sampling. For raw or dilute partial-flow emission sampling, to ensure mixing of the multiple exhaust streams before emission sampling, we recommend a minimum Reynolds number, Re#, of 4000 for the combined exhaust stream, where Re# is based on the inside diameter of the combined flow at the first sampling point. You may configure the exhaust system with turbulence generators, such as orifice plates or fins, to achieve good mixing; inclusion of turbulence generators may be required for Re# less than 4000 to ensure good mixing. Re# is defined in § 1065.640. For dilute full-flow (CVS) emission sampling, you may configure the exhaust system without regard to mixing in the laboratory section of the raw exhaust. For example you may size the laboratory section to reduce its pressure drop even if the Re#, in the laboratory section of the raw exhaust is less than 4000.

(3) Introduce raw exhaust into the tunnel by directing it downstream along the centerline of the tunnel. If you dilute directly from the exhaust stack, the end of the exhaust stack is considered to be the start of the dilution tunnel. You may introduce a fraction of dilution air radially from the tunnel's inner surface to minimize exhaust interaction with the tunnel walls. You may configure the system with turbulence generators such as orifice plates or fins to achieve good mixing. We recommend a minimum Reynolds number, Re #, of 4000 for the diluted exhaust stream, where Re # is based on the inside diameter of the dilution tunnel. Re # is defined in § 1065.640.

(9) Calibrate the PDP by using the collected data and the equations in § 1065.640.

(a) A propane check uses either a reference mass or a reference flow rate of C3H8 as a tracer gas in a CVS. Note that if you use a reference flow rate, account for any non-ideal gas behavior of C3H8 in the reference flow meter. Refer to §§ 1065.640 and 1065.642, which describe how to calibrate and use certain flow meters. Do not use any ideal gas assumptions in §§ 1065.640 and 1065.642. The propane check compares the calculated mass of injected C3H8 using HC measurements and CVS flow rate measurements with the reference value.

This section describes the equations for calculating molar flow rates from various flow meters. After you calibrate a flow meter according to § 1065.640, use the calculations described in this section to calculate flow during an emission test.

(viii) To ensure mixing of the multiple exhaust streams before emission sampling, we recommend a minimum Reynolds number, Re#, of 4000 for the combined exhaust stream, where Re# is based on the inside diameter of the combined flow at the first sampling point. You may configure the exhaust system with turbulence generators, such as orifice plates or fins, to achieve good mixing; this may be necessary for good mixing if Re# is less than 4000. Re# is defined in 40 CFR 1065.640.

This section describes the calculations for calibrating various flow meters based on mass flow rates. Calibrate your flow meter according to 40 CFR 1065.640 instead if you calculate emissions based on molar flow rates.

(4) Repeat the procedure in paragraphs (b)(1) through (3) of this section for every speed that you run your PDP.

(4) Repeat the procedure in paragraphs (b)(1) through (3) of this section for every speed that you run your PDP.

(4) Repeat the procedure in paragraphs (b)(1) through (3) of this section for every speed that you run your PDP.

(8) If the standard deviation of the remaining Cd still exceeds 0.3% of the mean of the remaining Cd values, repeat the steps in paragraph (e)(4) through (8) of this section.

(8) If the standard deviation of the remaining Cd still exceeds 0.3% of the mean of the remaining Cd values, repeat the steps in paragraph (e)(4) through (8) of this section.

(8) If the standard deviation of the remaining Cd still exceeds 0.3% of the mean of the remaining Cd values, repeat the steps in paragraph (e)(4) through (8) of this section.

(8) If the standard deviation of the remaining Cd still exceeds 0.3% of the mean of the remaining Cd values, repeat the steps in paragraph (e)(4) through (8) of this section.

(8) If the standard deviation of the remaining Cd still exceeds 0.3% of the mean of the remaining Cd values, repeat the steps in paragraph (e)(4) through (8) of this section.