Calculate slurry flow rate in a full pipe from inside diameter and velocity, or solve velocity or diameter, with optional density for mass flow.
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Understanding the Slurry Flow Rate Calculator
The Slurry Flow Rate Calculator solves full-pipe volumetric flow, average velocity or actual inside diameter from the other two quantities. Optional actual slurry density converts volume flow to total mass flow; optional solids concentration by weight splits that mass into dry-solids and liquid rates.
The geometry model uses Q = A × v for a full circular pipe. It does not assume water density, and it does not determine settling velocity, pressure loss, pump capability or wear.
Core Relationship
Pipe area A is calculated from actual inside diameter D. Volumetric flow Q equals area times cross-sectional average velocity v. Velocity is Q/A; the diameter solver uses D = sqrt(4Q/(πv)).
Where:
| Term | Meaning | Practical Interpretation |
|---|---|---|
| Inside diameter (D) | Actual circular pipe inside diameter | Determines flow area A = πD²/4 |
| Average velocity (v) | Cross-sectional average slurry speed | Used with flow area to calculate Q |
| Pipe area (A) | Full circular flow area | Express area in m² for SI equations |
| Volume flow (Q) | Volume passing per unit time | Q = A × v; density is optional for mass flow |
How to Enter the Inputs Correctly
- Use actual inside diameter. Nominal pipe size may differ from the flow area.
- Use cross-sectional average velocity. A local peak velocity is not the required average.
- Select each input unit. Diameter, velocity and flow have independent metric and US choices.
- Confirm the pipe is full. A partially full cross-section requires a different area model.
- Mass flow is optional. Enter actual bulk density; add weight percent only when dry-solids and liquid mass rates are needed.
What the Formula Is Really Doing
At fixed diameter, flow is proportional to average velocity. At fixed velocity, flow is proportional to diameter squared. Density and solids weight concentration affect the optional mass balance; they do not change the continuity result while diameter and velocity remain fixed.
- If average velocity increases at fixed diameter, Q increases proportionally.
- If inside diameter increases at fixed velocity, Q increases with diameter squared.
- If inside diameter increases at fixed Q, the required average velocity decreases with diameter squared.
Example Calculation
For an illustrative full-pipe example, use an actual inside diameter of 100 mm (0.100 m) and average velocity of 2.5 m/s. Optionally use an actual slurry density of 1,350 kg/m³ and solids concentration of 40% by weight.
The volume flow is approximately 0.01963495 m³/s, or 70.6858 m³/h (311.2204 US gal/min). With the optional density and concentration, total mass flow is 95.4259 metric t/h: 38.1704 t/h dry solids and 57.2555 t/h liquid.
Using Percent Solids by Weight
Enter actual bulk slurry density to calculate total mass flow. To split that mass into dry solids and liquid, also enter solids concentration Cw as percent by weight, with w = Cw/100. Weight concentration requires density; both 0% and 100% endpoints are valid.
Leave both optional fields blank when only pipe geometry and volume flow are needed. Weight percent is not volume percent. If SG is selected for density, the calculator uses the explicitly fixed reference 1 SG = 1,000 kg/m³.
Why the Result Is Approximate
Continuity is the stated model relationship; practical accuracy depends on actual inside diameter, a representative cross-sectional average velocity and a pipe flowing full. Optional mass results also depend on representative bulk density and weight concentration at the same operating conditions.
For Q in m³/s and actual density ρ in kg/m³, total mass flow is in kg/s. Multiply kg/s by 3.6 for metric t/h or by 3,600/0.45359237 for lb/h. No water-density or short-ton conversion constant is assumed.
When This Calculator Is Most Useful
- Continuity checks within separately assessed pump and piping systems
- Converting known slurry volume flow to mass flow using actual bulk density
- Finding average velocity or inside diameter from a specified volume-flow condition
- Comparing diameter, velocity and flow changes under consistent operating assumptions
- Screening, classification, flotation, and thickener feed evaluations
Common Input Mistakes to Avoid
- Using nominal instead of actual inside diameter. The area depends on inside diameter squared.
- Using a partially full pipe or local peak velocity. The model requires a full cross-section and average velocity.
- Using solid-particle density for bulk slurry density. Optional mass flow requires the actual mixture density.
- Using non-representative samples. Settling, segregation, or poor mixing can distort the solids fraction.
- Confusing weight fraction with volume fraction. This calculator uses mass-based concentration, not volumetric solids percentage.
Quick Interpretation Guide
| If this changes… | Effect on volume or mass flow | Reason |
|---|---|---|
| Average velocity increases (D fixed) | Volume flow increases proportionally | Q = A × v |
| Inside diameter increases (v fixed) | Volume flow increases with D² | A = πD²/4 |
| Actual density increases (Q fixed) | Total mass flow increases; Q is unchanged | Total mass flow = ρQ |
| Weight concentration increases (Q and ρ fixed) | Dry-solids mass rises; liquid mass falls; Q is unchanged | The solids and liquid weight fractions split total mass flow |
Practical Tip
Confirm the selected units and full-pipe assumptions before using the result. A continuity diameter is a geometry result, not a recommended hydraulic design. Assess settling, particle size, rheology, pressure loss, pump limits and wear separately.
