.calculator-wrapper {
font-family: sans-serif;
max-width: 600px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.calculator-inputs {
display: grid;
grid-template-columns: repeat(2, 1fr);
gap: 15px;
margin-bottom: 20px;
}
.form-group {
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
}
.form-group input {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
}
button {
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
transition: background-color 0.3s ease;
}
button:hover {
background-color: #0056b3;
}
#result {
margin-top: 20px;
padding: 15px;
background-color: #e9ecef;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 1.1em;
text-align: center;
}
function calculatePumpRequirements() {
var boilerCapacity = parseFloat(document.getElementById("boilerCapacity").value);
var steamQuality = parseFloat(document.getElementById("steamQuality").value);
var feedWaterTemp = parseFloat(document.getElementById("feedWaterTemp").value);
var requiredPressure = parseFloat(document.getElementById("requiredPressure").value);
var pumpEfficiency = parseFloat(document.getElementById("pumpEfficiency").value);
var pipeFrictionLoss = parseFloat(document.getElementById("pipeFrictionLoss").value);
var safetyFactor = parseFloat(document.getElementById("safetyFactor").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(boilerCapacity) || isNaN(steamQuality) || isNaN(feedWaterTemp) ||
isNaN(requiredPressure) || isNaN(pumpEfficiency) || isNaN(pipeFrictionLoss) ||
isNaN(safetyFactor)) {
resultDiv.innerHTML = "Please enter valid numerical values for all fields.";
return;
}
if (steamQuality 100) {
resultDiv.innerHTML = "Steam quality must be between 0% and 100%.";
return;
}
if (pumpEfficiency 100) {
resultDiv.innerHTML = "Pump efficiency must be between 1% and 100%.";
return;
}
if (safetyFactor <= 0) {
resultDiv.innerHTML = "Safety factor must be greater than 0.";
return;
}
// Constants (approximate values)
var specificVolumeWaterAt100C = 0.001044; // m³/kg (approximate specific volume of water at 100°C)
var densityWaterAt100C = 1 / specificVolumeWaterAt100C; // kg/m³
var specificHeatWater = 4.18; // kJ/kg°C
var latentHeatVaporization = 2257; // kJ/kg (approximate at 1 bar)
var densityWaterAtFeedTemp = 1000; // kg/m³ (assuming feed water at ~20-30C for simplicity, density is close to 1000)
// 1. Calculate feed water flow rate (kg/hr)
// Assuming all boiler capacity is steam output, adjust for quality.
// The feed water must compensate for the water turned into steam and blowdown.
// For simplicity, we'll assume blowdown is negligible or included in efficiency implicitly.
// Feed water flow = Boiler Capacity / Steam Quality (if quality is < 100%)
var feedWaterFlowKgHr = boilerCapacity / (steamQuality / 100.0);
// 2. Convert flow rate to m³/hr (using density at feed water temperature)
var feedWaterFlowM3Hr = feedWaterFlowKgHr / densityWaterAtFeedTemp;
// 3. Calculate Total Dynamic Head (TDH) in meters
// TDH = Static Head + Friction Head + Pressure Head + Safety Margin
// First, convert pressure to head (meters of water column)
// Pressure (Pa) = Density (kg/m³) * Gravity (m/s²) * Head (m)
// 1 bar = 100,000 Pa
var requiredPressurePa = requiredPressure * 100000;
var pipeFrictionLossPa = pipeFrictionLoss * 100000;
var gravity = 9.81; // m/s²
// Assuming static head is negligible for most boiler feed pump scenarios where the pump is near the boiler.
// If there's a significant lift, a 'Static Head' input would be needed.
var staticHeadMeters = 0; // Placeholder for potential static lift
var pressureHeadMeters = requiredPressurePa / (densityWaterAtFeedTemp * gravity);
var frictionHeadMeters = pipeFrictionLossPa / (densityWaterAtFeedTemp * gravity);
// Total head required to overcome boiler pressure and piping losses.
// The safety factor is applied to the total head requirement.
var totalHeadRequiredMeters = (pressureHeadMeters + frictionHeadMeters) * safetyFactor;
// 4. Calculate required pump power (kW)
// Hydraulic Power (kW) = (Flow Rate (m³/s) * TDH (m) * Density (kg/m³) * Gravity (m/s²)) / 1000
// Convert m³/hr to m³/s
var feedWaterFlowM3S = feedWaterFlowM3Hr / 3600.0;
var hydraulicPowerKw = (feedWaterFlowM3S * totalHeadRequiredMeters * densityWaterAtFeedTemp * gravity) / 1000.0;
// Brake Horsepower (BHP) = Hydraulic Power (kW) / Pump Efficiency (%)
var brakeHorsepowerKw = hydraulicPowerKw / (pumpEfficiency / 100.0);
// Convert kW to HP if desired (1 kW = 1.341 HP)
var brakeHorsepowerHp = brakeHorsepowerKw * 1.341;
// Display results
var outputHtml = "
Boiler feed pumps are critical components in steam generation systems, responsible for supplying feedwater to the boiler at a pressure and flow rate sufficient to meet the steam demand. Accurate calculation of the required pump performance is essential for efficient and safe boiler operation.
Key Factors in Calculation:
Boiler Capacity (kg/hr): This is the maximum rate at which the boiler can produce steam. The feed pump must be able to supply at least this much water.
Steam Quality (%): If the steam produced is not 100% dry (i.e., it contains some water vapor), the feed water flow rate needs to be higher than the boiler capacity to compensate for the moisture in the steam. A quality of 95% means 5% of the output is liquid water, so the feed rate needs to be 1 / 0.95 times the boiler capacity.
Feed Water Temperature (°C): This affects the density of the water being pumped, which is used in head calculations. Higher temperatures mean lower density and thus slightly higher volume flow rate for the same mass flow rate.
Required Boiler Pressure (bar): The pump must deliver water at a pressure at least equal to the operating pressure inside the boiler.
Pump Efficiency (%): Pumps are not 100% efficient. This factor accounts for internal losses and is used to determine the actual power required by the pump motor.
Total Friction Loss in Piping (bar): As water flows through pipes, valves, and fittings, there is a pressure drop due to friction. This loss must be overcome by the pump.
Safety Factor (dimensionless): A multiplier applied to the calculated head to account for uncertainties, future degradation of piping, and ensuring the pump operates reliably without being undersized. A typical value might be 1.1 to 1.25.
How the Calculation Works:
Feed Water Flow Rate: The primary calculation is determining the mass flow rate of water the pump needs to deliver. This is typically the boiler capacity divided by the steam quality (expressed as a decimal).
Total Dynamic Head (TDH): This is the total equivalent pressure the pump must generate. It includes:
Pressure Head: The pressure inside the boiler, converted into an equivalent height of a water column.
Friction Head: The pressure loss in the piping system, also converted into an equivalent height of a water column.
Static Head (if applicable): The vertical distance the water needs to be lifted from the source to the boiler. For many industrial boiler feed systems, the pump is located close to the boiler, making static head negligible.
The calculated head is then multiplied by the Safety Factor.
Required Pump Power: Using the flow rate (converted to m³/s) and the TDH, the hydraulic power required to move the water is calculated. This is then divided by the pump's efficiency to find the actual power the motor must provide (Brake Horsepower or BHP).
This calculator provides an estimate based on common formulas. For critical applications, consult with pump manufacturers and engineering professionals.