Need the template? Reply below with your gas composition and temperature—I'll share a link to the .xlsx file with macros for the flooding chart.
Tag your design team. 🔥 Spreadsheets save lives (and budgets).
Designing a scrubber, specifically for "hot" or high-temperature gas streams, requires accounting for gas humidification and volume changes before sizing the vessel. You can find pre-built templates on platforms like Scribd or Cheresources that handle these calculations. Core Calculation Steps for Hot Gas Scrubbers
For high-temperature applications, the "hot" gas must be cooled to its adiabatic saturation temperature before or during the scrubbing process. Gas Inlet Properties: Define your inlet gas temperature ( Tincap T sub i n end-sub
), flow rate, and pressure. Hot gases have lower density, which significantly increases the required tower diameter.
Saturation & Humidity: Calculate the saturated gas flow rate. For example, a gas at 400°F may have a saturation temperature around 127°F, which changes the volumetric flow rate ( Qsatcap Q sub s a t end-sub ) used for sizing.
Liquid-to-Gas (L/G) Ratio: This is the most critical design parameter. For venturi scrubbers, typical ratios are 7–20 gallons per 1,000 cubic feet of gas.
Tower Diameter: Use the gas velocity and pressure drop to find the cross-sectional area. The diameter ( ) is typically calculated as Pressure Drop ( ΔPcap delta cap P
): For venturi types, use the Hesketh or Calvert equations to ensure the fan can handle the resistance. Recommended Excel Templates
Excel calculation sheet for rating of a spray tower scrubber
To get a highly accurate wet scrubber design calculation Excel sheet, you must account for thermal effects, evaporation, and gas expansion when handling hot gas streams.
Below is the complete step-by-step framework to build your own robust design spreadsheet in Excel. 📊 Core Spreadsheet Input Parameters
To begin your calculations, set up an Inputs Section in your Excel sheet with the following variables: Gas Properties: Inlet Gas Flow Rate ( Qg,incap Q sub g comma i n end-sub ) in or CFMcap C cap F cap M . Inlet Gas Temperature ( Tincap T sub i n end-sub ) in ∘Craised to the composed with power cap C . Gas Molecular Weight ( MWgcap M cap W sub g ). Liquid Properties: Scrubbing Liquid (usually water) Inlet Temperature ( TL,incap T sub cap L comma i n end-sub ). Liquid Density ( ρLrho sub cap L ). Pollutant Data: Inlet Concentration ( Cincap C sub i n end-sub ). Desired Outlet Concentration ( Coutcap C sub o u t end-sub ) or target efficiency. ⚙️ Step-by-Step Design Calculations
Use these sequential formulas to build out the active calculating cells in your Excel grid. 1. Hot Gas Quenching & Saturation
Hot gases will immediately evaporate a portion of the scrubbing liquid upon contact, cooling the gas to its adiabatic saturation temperature. Excel Goal: Calculate the saturated gas flow rate ( Qg,satcap Q sub g comma s a t end-sub ).
Concept: Use the ideal gas law to account for volume shrinkage due to cooling, balanced against volume increase from added water vapor. Formula Clue: 2. Tower Diameter (Flooding Velocity Method)
To prevent the liquid from being blown out of the top of the scrubber, you must calculate the tower's cross-sectional area based on the gas velocity. Action: Calculate the Flooding Gas Velocity ( Ufcap U sub f ) using the Sherwood-Lobo Correlation. Excel Formula:Set your operating velocity ( Uopcap U sub o p end-sub ) at 60% to 70% of the flooding velocity.
Tower Area (A)=Qg,satUopTower Area open paren cap A close paren equals the fraction with numerator cap Q sub g comma s a t end-sub and denominator cap U sub o p end-sub end-fraction
Diameter (D)=4×AπDiameter open paren cap D close paren equals the square root of the fraction with numerator 4 cross cap A and denominator pi end-fraction end-root 3. Packing Height (Mass Transfer)
This determines how tall your packed bed needs to be to achieve your removal efficiency. Formula:
HTU (Height of a Transfer Unit): Characterizes the mass transfer efficiency of your chosen packing material. NTU (Number of Transfer Units): for lean systems. 4. Liquid-to-Gas (L/G) Ratio
For effective particulate and acid gas removal, typical L/G ratios range from 1 to 3 liters of liquid per cubic meter of gas.
Ensure your pump sizing in Excel accounts for this total volume. ⚠️ Critical Checks for "Hot" Gas Scrubbers If your incoming gas is over 150∘C150 raised to the composed with power cap C ( 300∘F300 raised to the composed with power cap F
), you must build these safety checks into your Excel sheet:
Materials of Construction (MOC): Standard fiberglass (FRP) or plastics like PVC will melt. Your spreadsheet should flag temperatures and recommend High-Temperature FRP, Hastelloy, or a brick-lined quench section.
Make-up Water Rate: Account for massive water loss due to evaporation. Your Excel sheet must calculate: .
To help me tailor a specific set of formulas or a ready-to-copy tabular layout for your sheet, could you tell me: What is the inlet temperature of your hot gas? What specific pollutant are you trying to scrub (e.g., SO2cap S cap O sub 2 , HClcap H cap C l , or just fly ash/dust)? Do you prefer your calculations in SI units (Celsius, ) or Imperial units (Fahrenheit, CFMcap C cap F cap M )?
Wet Scrubber: Efficiency Сalculation, L/G Ratio, and Pressure Drop
The first step is to establish the properties of the incoming hot gas. Because the gas is "hot," you must account for its actual volume at operating temperature rather than standard conditions. Gas Flow Rate ( Vincap V sub i n end-sub ): Define in ACFM (Actual Cubic Feet per Minute) or Inlet Temperature ( Tincap T sub i n end-sub ): Note the temperature (e.g., 400∘F400 raised to the composed with power cap F 590∘C590 raised to the composed with power cap C
Contaminant Data: Identify the molecular weight and concentration (ppm or ) of the component to be removed (e.g., HCl, H2Scap H sub 2 cap S Gas Properties: Calculate gas density ( ρgrho sub g
) at inlet temperature and pressure using the Ideal Gas Law. 2. Perform Humidification and Saturation Calculations
Hot gases will evaporate the scrubbing liquid until they reach the adiabatic saturation temperature ( Tsatcap T sub s a t end-sub
). The scrubber must be sized for the saturated gas volume, not the inlet volume. Determine Saturation Temperature ( Tsatcap T sub s a t end-sub
): Use a psychrometric chart or humidity balance to find the temperature at which the gas becomes saturated with moisture. Calculate Saturated Gas Flow ( Qsatcap Q sub s a t end-sub ):
Qsat=Qin×Volume Correction Factorcap Q sub s a t end-sub equals cap Q sub i n end-sub cross Volume Correction Factor For example, a gas at 450∘F450 raised to the composed with power cap F might have a correction factor of 3. Determine Column Diameter
The tower diameter is typically calculated to avoid "flooding," where upward gas velocity prevents downward liquid flow.
Select Packing Material: Choose a packing type (e.g., Intalox Saddles, Rosette) and its specific Packing Factor ( Fpcap F sub p ).
Calculate Flooding Velocity: Use the Generalized Pressure Drop Correlation (GPDC). Aim for an operating velocity between of the flooding velocity. Find Cross-Sectional Area ( Ascap A sub s ):
As=Qsatvgascap A sub s equals the fraction with numerator cap Q sub s a t end-sub and denominator v sub g a s end-sub end-fraction vgasv sub g a s end-sub is the selected design gas velocity (e.g., Final Diameter ( ):
D=4×Asπcap D equals the square root of the fraction with numerator 4 cross cap A sub s and denominator pi end-fraction end-root 4. Determine Packing Height
The required height depends on the mass transfer efficiency needed to meet outlet concentration targets.
HCL Packed Column Scrubber Design | PDF | Mole (Unit) - Scribd scrubber design calculation excel hot
🔥 Master Your Scrubber Design: Hot Gas Stream Excel Guide
Designing a scrubber for "hot" gas streams requires more than just standard absorption formulas. You must account for gas cooling, adiabatic saturation, and volume expansion. Use this structure to build a robust Excel calculator. 1. Core Inputs (The Essentials) Gas Stream Data: Inlet temperature ( Tincap T sub i n end-sub ), mass flow rate ( ṁgasm dot sub g a s end-sub ), and initial pollutant concentration ( Cincap C sub i n end-sub Target Efficiency: Desired removal percentage (e.g., 99%). Liquid-to-Gas (L/G) Ratio: Typically for wet systems. 2. Key Design Formulas for your Excel Cells Saturation Temperature ( Tsatcap T sub s a t end-sub
): The gas must be cooled before effective scrubbing. Calculate the adiabatic saturation temperature to determine the final volume. Scrubber Capacity:
Blower Capacity (per hour) = Total Air Flow Rate (m³) / Time. Removal Efficiency ( ): Excel Formula: =(Entry_Conc - Exit_Conc) / Entry_Conc. L/G Ratio: Use the Torch-Air standard of gallons per ft3f t cubed of air for high-performance units. 3. Pro-Tips for "Hot" Scrubber Sizing
Material Selection: Hot gas often requires exotic alloys or specialized FRP (Fiber Reinforced Plastic). Ensure your Excel includes a "Material Factor" lookup table.
Volume Expansion: Remember that hot gas occupies more volume (
). Your blower CFM must be sized for the actual temperature, not just standard conditions.
Water Evaporation: Calculate the water lost to evaporation to ensure your pump and hydro-tanks are sized correctly.
Looking for a pre-built template? Check out engineering resources like the Microsoft Support Guide for help with complex cell logic or Torch-Air's Engineering Blog for the full physics breakdown.
Wet Scrubber Design: Steps, Parameters, Calculation, Equations
When searching for "scrubber design calculation excel hot", do not settle for a static PDF or a generic absorber sheet. You require a dynamic workbook that solves the adiabatic cooling curve, corrects gas density, and checks thermal survival of droplets.
Checklist for your ideal Excel tool:
By mastering these calculations, you move from guesswork to precision engineering—ensuring your hot gas scrubber operates safely, efficiently, and without thermal failure.
Need a template? Look for downloadable workbooks that include VBA macros for iterative solving, as standard Excel formulas cannot handle the circular logic required for true hot gas adiabatic saturation.
Introduction
A scrubber is a type of air pollution control device that uses a liquid to remove contaminants and pollutants from a gas stream. The design of a scrubber involves several key calculations to ensure that it can effectively remove pollutants and meet emissions standards. In this write-up, we will discuss how to perform scrubber design calculations using Excel.
Scrubber Design Calculations
The design of a scrubber involves several key calculations, including:
Excel Calculation Template
To perform scrubber design calculations in Excel, we can create a calculation template that includes the following inputs:
The template can then be used to calculate the following outputs:
Step-by-Step Calculation Procedure
Here is a step-by-step procedure for performing scrubber design calculations in Excel:
Example Calculation
Here is an example calculation for a scrubber design using Excel:
Using the calculation template and step-by-step procedure, we can calculate the following outputs:
Conclusion
Scrubber design calculations can be performed using Excel to ensure that a scrubber can effectively remove pollutants and meet emissions standards. By following a step-by-step calculation procedure and using a calculation template, engineers can quickly and accurately design scrubbers for a variety of applications.
The design of a wet scrubber—whether for particulate removal or gas absorption—requires a systematic calculation process to determine critical dimensions and operational parameters. Utilizing a structured Excel spreadsheet
allows engineers to quickly iterate through design variables like gas flow rates, temperature, and pressure drops to find an optimal configuration. 1. Define Design Inputs and Gas Conditions
The first step is establishing the "source" data. In an Excel sheet, these are typically grouped in a dedicated "Inputs" tab. Gas Stream Properties : Include the inlet volumetric flow rate (e.g., in ), inlet temperature, and pressure. Saturation Calculations
: For hot gases, the scrubber will saturate the stream. You must calculate the saturated gas flow rate cap Q sub s a t end-sub ) and temperature ( cap T sub s a t end-sub
) using a psychrometric chart or humidity ratios. The scrubber is sized based on this saturated outlet volume, not the hot inlet volume. Target Efficiency : Define the required collection efficiency (e.g., for particulates) based on regulatory standards. 2. Determine Column Diameter The column diameter ( ) is primarily a function of the gas velocity required to avoid flooding while maintaining contact time. Calculation
: Divide the saturated volumetric flow rate by the allowable shell velocity (typically around for spray towers). Cross-Sectional Area ( cap A sub s
cap A sub s equals the fraction with numerator cap Q sub s a t end-sub and denominator v end-fraction Diameter (
cap D equals the square root of the fraction with numerator 4 cross cap A sub s and denominator pi end-fraction end-root Hydraulic Check : For packed towers, the Excel sheet should check the % Flooding (typically designed for
) using correlations like Norton’s to ensure the gas can move through the packing without pushing the liquid back up. 3. Calculate Tower Height and Packing
The height ensures sufficient contact time between the gas and the scrubbing liquid. Wet scrubber design calculation xls
Designing a wet scrubber for high-temperature ("hot") gas streams requires balancing pollutant removal efficiency with heat recovery and structural integrity
. Using Excel allows for iterative modeling of these complex thermal and chemical interactions. www.mchip.net Core Design Parameters
A proper design calculation must start with these foundational inputs: Gas Characteristics : Volumetric flow rate ( cap Q sub g ), inlet temperature ( cap T sub i n end-sub ), moisture content, and pollutant concentration (e.g., cap H sub 2 cap S cap S cap O sub 2 , or particulate matter). Removal Requirements : Desired outlet concentration ( cap C sub o u t end-sub ) and overall absorption efficiency ( Saturation State : For hot gases, calculating the saturation temperature ( cap T sub s a t end-sub Need the template
) and saturated volume is critical for sizing the shell diameter. www.mchip.net Step-by-Step Calculation Logic in Excel Gas Volume Correction
: Hot gas volume must be corrected to saturated conditions. For example, a 10,000 ACFM stream at 450°F may reduce to 7,500 ACFM upon saturation. Tower Sizing
: Determine based on the allowable gas velocity through the shell (typically 1–2 m/s or 500 ft/min).
: Calculated using the Height of a Transfer Unit (HETP) and the required Number of Transfer Units (NTU) based on absorption kinetics. Liquid-to-Gas (L/G) Ratio
: This ratio (typically 0.1 to 10) determines the volume of scrubbing liquid needed to handle the pollutant load and provide necessary cooling. Pressure Drop ( cap delta cap P : Use correlations like Norton’s Darcy-Weisbach
equation to ensure the system operates within fan/blower limits. : For hot gases, calculate the energy balance (
) to determine the cooling load or potential for heat recovery. www.mchip.net Excel Implementation Resources
For a professional starting point, utilize these established templates: EPA Cost & Design Spreadsheets US EPA Cost Calculation Spreadsheets
provide detailed tabs for Packed Bed and Wet Flue Gas Desulfurization (WFGD) parameters. Spray Tower Calculators : Marco Meloni offers a specialized Spray Tower Excel Sheet that covers removal efficiency and pressure losses. General Wet Scrubber Sheets
: Detailed sizing guides for diameter, plate thickness, and packing selection can be found on platforms like H2s Scrubber Design Calculation - MCHIP
Scrubber Design Calculation using Excel
A scrubber is a type of air pollution control device that uses a liquid to remove contaminants and pollutants from gas streams. Designing a scrubber requires careful calculation of various parameters to ensure effective performance. Here's a step-by-step guide on how to perform scrubber design calculations using Excel:
Step 1: Define Design Parameters
Step 2: Calculate Scrubber Diameter
The scrubber diameter (D) can be calculated using the following formula:
D = √(4 * Qg / (π * Vg))
where Vg is the gas velocity (m/s or ft/s)
Assuming a typical gas velocity of 3-5 m/s, let's use 4 m/s for this example.
| | | | --- | --- | | Qg (m³/s) | 1 | | Vg (m/s) | 4 | | D (m) | =SQRT(4*1/(PI()*4)) | =0.89 m |
Step 3: Calculate Scrubber Height
The scrubber height (H) can be calculated using the following formula:
H = (L/D) * D
where L/D is the aspect ratio (typically 3-5)
Assuming an aspect ratio of 4, let's use L/D = 4 for this example.
| | | | --- | --- | | L/D | 4 | | D (m) | 0.89 | | H (m) | =4*0.89 | =3.56 m |
Step 4: Calculate Liquid-to-Gas Ratio (L/G)
The liquid-to-gas ratio (L/G) is a critical parameter in scrubber design. A higher L/G ratio typically results in better contaminant removal, but also increases the energy consumption.
L/G = Ql / Qg
| | | | --- | --- | | Ql (m³/s) | 0.01 | | Qg (m³/s) | 1 | | L/G | =0.01/1 | =0.01 |
Step 5: Calculate Contaminant Removal Efficiency
The contaminant removal efficiency (η) can be calculated using the following formula:
η = (C_in - C_out) / C_in
where C_in is the inlet contaminant concentration and C_out is the outlet contaminant concentration.
Assuming a target removal efficiency of 90%, let's use η = 0.9 for this example.
| | | | --- | --- | | C_in (ppm) | 100 | | η | 0.9 | | C_out (ppm) | =(1-0.9)*100 | =10 ppm |
Excel Template
Here's an example Excel template that you can use to perform scrubber design calculations:
| Parameter | Value | Unit | | --- | --- | --- | | Gas flow rate (Qg) | | m³/s | | Gas temperature (Tg) | | °C | | Gas pressure (Pg) | | Pa | | Liquid flow rate (Ql) | | m³/s | | Liquid temperature (Tl) | | °C | | Contaminant concentration (C) | | ppm | | Scrubber diameter (D) | | m | | Scrubber height (H) | | m | | Liquid-to-gas ratio (L/G) | | - | | Contaminant removal efficiency (η) | | - |
You can download a sample Excel template from [insert link].
Conclusion
Scrubber design calculations involve several steps, including defining design parameters, calculating scrubber diameter and height, determining liquid-to-gas ratio, and estimating contaminant removal efficiency. By using Excel templates, you can simplify these calculations and optimize your scrubber design. Remember to validate your results with experimental data or simulation models to ensure accurate performance. Tag your design team
Designing a wet scrubber for hot gas streams—such as flue gas from industrial combustion—requires balancing mass transfer with significant thermal changes. The following guide outlines the core design calculations, specifically tailored for an Excel-based implementation, focusing on the unique challenges of "hot" inlet gases. Core Scrubber Design Process
The design of a scrubber for hot gases is an iterative process that begins with understanding the physical properties of the gas at its saturated state. 1. Calculate Adiabatic Saturation Temperature ( Tsatcap T sub s a t end-sub
When a hot gas enters a wet scrubber, it is cooled by the evaporation of the scrubbing liquid. For engineering purposes, the gas is assumed to reach its adiabatic saturation temperature. In Excel, you can solve for Tsatcap T sub s a t end-sub using the following energy balance:
s(Tin−Tsat)=λ(Hsat−Hin)s open paren cap T sub i n end-sub minus cap T sub s a t end-sub close paren equals lambda open paren cap H sub s a t end-sub minus cap H sub i n end-sub close paren : Humid heat of the gas. Tincap T sub i n end-sub : Inlet gas temperature. : Latent heat of vaporization at Tsatcap T sub s a t end-sub
: Initial and saturation humidity ratios (lb water/lb dry gas). Excel Tip: Use the Excel Solver Add-in to find the Tsatcap T sub s a t end-sub that balances this equation, as Hsatcap H sub s a t end-sub are both temperature-dependent. 2. Determine Saturated Gas Flow Rate ( Qsatcap Q sub s a t end-sub
Hot gases occupy a larger volume than cooled gases. Once you have Tsatcap T sub s a t end-sub
, you must calculate the volumetric flow rate of the gas at this lower temperature to size the vessel correctly:
Qsat=Qin⋅TsatTin⋅PinPsat+Volume of Added Water Vaporcap Q sub s a t end-sub equals cap Q sub i n end-sub center dot the fraction with numerator cap T sub s a t end-sub and denominator cap T sub i n end-sub end-fraction center dot the fraction with numerator cap P sub i n end-sub and denominator cap P sub s a t end-sub end-fraction plus Volume of Added Water Vapor
Calculations must be performed on a dry gas basis to account for the additional water vapor added during cooling. 3. Sizing the Tower Diameter Individual Design of 2 Scrubbers - UKDiss.com
* 2.2.2.3 Calculation of % flooding. From Figure 1, K4 at flooding = 8. % flooding: 100*K4K4 flooding0.5=100*380.5=61.24% * 2.2.2. UKDiss.com
Venturi Scrubber Design Calculations | PDF | Gases | Liquids - Scribd
Designing a scrubber for hot gas streams requires calculating the column diameter, height, and cooling capacity to ensure efficient pollutant removal . Excel-based design tools typically focus on mass transfer pressure drop correlations to determine these dimensions. assets-global.website-files.com Key Design Parameters for Hot Gas Scrubbers Gas Inlet Conditions : You must input the initial temperature (e.g., 400 raised to the composed with power cap F 70 raised to the composed with power cap C ) and flow rate to account for gas expansion. Humidification & Cooling
: Scrubbers reduce gas temperature to saturation conditions (e.g., down to 59 raised to the composed with power cap C ) while increasing relative humidity. Column Diameter
: Calculated based on the gas mass flow rate and a target "percentage of flooding" (typically 50–85%) to avoid liquid backup. Height of Packing (HETP) : Determined using correlations like Norton’s to ensure enough contact time for chemical absorption. Pressure Drop ( cap delta cap P
: Essential for sizing the fan or blower motor; usually calculated for both irrigated and dry packing. assets-global.website-files.com Scrubber Design Excel Resources
The following platforms provide templates and detailed spreadsheets for scrubber sizing: Wet Scrubber Design Excel Sheet | PDF - Scribd
For designing and calculating wet scrubbers in Excel, there are several specialized templates and resources available that cover hydraulic design, mass transfer, and cost estimation. Excel Calculation Templates Spray Tower Scrubber Rating: Meloni Marco
offers a downloadable spreadsheet for preliminary single-stage spray tower calculations, including removal efficiency and pressure losses.
EPA Scrubber Cost & Design: The U.S. EPA provides comprehensive workbooks like the Wet & Dry FGD Data Inputs
and cost calculation spreadsheets for packed bed and flue gas desulfurization (FGD) systems.
Packed Bed Design: Engineering forums like Cheresources host community-shared files such as scrubber_design.xls and Packed bed+ hetp.xls for tower sizing. Wet Scrubber Design Excel Sheet | PDF - Scribd
The hum of the plant was usually a comfort to Elias, but today, the caustic scrubber
was screaming. Not literally, of course—though the high-pressure alarm on the control panel was doing a fine job of that.
The inlet gas temperature from the kiln had spiked, and the old design parameters were failing. If the liquid-to-gas ratio stayed this off-balance, the stack would start "yellow-smoking," and the EPA would be at the gates by noon.
Elias ducked into the site office, his boots clacking on the linoleum. He pulled up his master file: Scrubber_Design_Final_v4_HOT.xlsx
"Talk to me," he muttered, fingers flying across the mechanical keyboard. He didn't just need a fix; he needed a recalculation for adiabatic saturation
. As the hot gas hit the recirculating liquor, it would evaporate water instantly, cooling the gas but shrinking its volume and changing the density. The Inputs:
He punched in the new 450°F inlet temp and the soaring flow rate. The Magic:
The spreadsheet’s hidden VLOOKUPs pulled the physical properties of the gas. The NTU (Number of Transfer Units) cells turned a cautionary orange. The Solve:
He adjusted the packing depth from 10 feet to 14. The pressure drop calculation—the heart of the sheet—recalculated.
With a final tweak to the pump frequency on the screen, he watched the "Flood Point %" drop from a dangerous 92% to a stable 70%. He hit 'Save,' exported the setpoints, and ran back to the floor.
Ten minutes later, the alarm fell silent. The plume at the top of the stack turned from a ghost of a haze to invisible, clean air. Elias leaned against the steel railing, the heat of the tower radiating against his back, and smiled.
The math held. The Excel sheet, messy as it was, had saved the day. pressure drop across the packing for your own design?
This write-up covers the thermodynamic principles, the step-by-step calculation logic required for the Excel model, and the critical design parameters.
The gas will cool to the adiabatic saturation temperature (typically 40°C to 70°C depending on water temperature).
Equation:
m_gas * Cp_gas * (T_in - T_out) = m_water * λ
Where λ is the latent heat of vaporization of water.
Standard scrubber design assumes isothermal conditions or negligible temperature drop. For hot streams (typically >150°F / 65°C up to 1800°F), the physics shift dramatically:
A "cold" spreadsheet fails here. You need an iterative Excel model.
If you don't want to rebuild the wheel from scratch, here are your options:
This is the critical design constraint.
$$ \Delta P = \fracu_t^2 \times L \times \rho_l1000 \times C_d \quad \text(Simplified units) $$
A more robust Excel formula using the Hesketh Equation: $$ \Delta P \approx \fracu_t^2 \rho_g A_t^0.1331270 \times \left( L/G \right) $$ (Note: Ensure consistent units: Pa or in. w.c.)