Heat Capacity

Heat capacity (Cp) is calculated using polynomial correlations.

Correlation

Cp(T) = a + b*T + c*T² + d*T³

Where:

• T is temperature in Kelvin
• a, b, c, d are component-specific coefficients
• Cp is in J/(mol·K)

Implementation

export function getCp(componentId: string, T_K: number): number {
  const comp = componentData[componentId];
  if (!comp?.Cp_coef) return 29.1;
  
  const [a, b, c, d] = comp.Cp_coef;
  return a + b * T_K + c * T_K ** 2 + d * T_K ** 3;
}

Example Values

Component	Cp at 298K
Water	33.6 J/(mol·K)
Methane	35.7 J/(mol·K)
Nitrogen	29.1 J/(mol·K)

Mixture Heat Capacity

export function getMixtureCp(composition: Record<string, number>, T_K: number): number {
  let totalCp = 0;
  for (const [compId, moleFrac] of Object.entries(composition)) {
    totalCp += moleFrac * getCp(compId, T_K);
  }
  return totalCp;
}