Scientific tool, not a clinical device.
This simulator provides model-based estimates. The calculated temperature, SAR, relaxation behavior, and heating rate depend strongly on assumptions regarding particle size, magnetic anisotropy, magnetic properties, thermal properties, suspension behavior, and experimental conditions. The model should be calibrated and validated against experimental measurements before scientific conclusions are drawn.
1 Experimental Data (optional)
Result
Simulation Summary
Experimental Calibration
Temperature vs Time
Delta Temperature vs Time
Heating Rate vs Time
Relaxation Parameters (log scale)
Magnetic Heating Power & Heat Loss
Model Calculation (audit trace)
Every intermediate quantity at the first and last time step, in SI units.
Parameters Used
Compare Simulations
Each scenario starts from the current form parameters and overrides frequency, field, concentration and viscosity. Maximum 10 scenarios.
| Label | f (kHz) | H (kA/m) | C (ppm) | η (Pa·s) |
|---|
Sensitivity Analysis
Model Assumptions
- Spherical nanoparticle geometry
- Uniform (monodisperse) particle properties — no size distribution
- Homogeneous, dilute suspension
- Uniform temperature approximation (lumped thermal model)
- No spatial temperature gradient
- Simplified relaxation model (Debye-type x/(1+x²) response, linear response theory)
- Zero-field Néel–Arrhenius relaxation (no field-dependent energy barrier)
- Empirical magnetic field response (exponent n)
- Empirical concentration response (linear or saturating)
- Constant saturation magnetization, anisotropy and viscosity (no temperature dependence except through T in τN, τB, χ0)
- Newtonian (linear) heat loss with constant effective coefficient h_loss
- No explicit convection model
- No radiation model
- No aggregation / chain-formation model
- No boiling / evaporation model
- Effective heat capacity — not a calorimetric measurement
- Advanced parameter defaults are MODEL ASSUMPTIONS, not experimental results
Model equations
| Unit conversion | T[K] = T[°C] + 273.15; f[Hz] = f[kHz]·1000; H[A/m] = H[kA/m]·1000; C[kg/m³] = ppm·1e-6·ρ_fluid |
|---|---|
| Particle volumes | V = π d³ / 6; V_h = π d_h³ / 6 |
| Néel relaxation | τN = τ0 · exp(K V / (kB T)) (exponent capped for numerical safety) |
| Brownian relaxation | τB = 3 η V_h / (kB T) |
| Effective relaxation | 1/τeff = 1/τN + 1/τB |
| Relaxation response (simplified) | ω = 2πf; x = ω τeff; F_relax = x / (1 + x²) (Relaxation-Based mode only) |
| Frequency factor | Relaxation-Based: F_f = f / f_ref; Simplified: F_f = (f / f_ref)^m; F_f ≤ F_f,max |
| Field factor (empirical) | F_H = (H / H_ref)^n, F_H ≤ F_H,max |
| Concentration factor | saturating: F_C = (C/C_ref)·(C_ref + C_sat)/(C + C_sat); linear: F_C = C/C_ref (capped) |
| Equilibrium susceptibility | χ0 = μ0 φ Ms² V / (3 kB T), φ = C / ρ_particle |
| Reference power | Relaxation-Based: P_ref(T) = μ0 π χ0(φ_ref, T) H_ref² f_ref V_sample; Simplified: P_ref = P0 |
| Magnetic heating power | P_mag = α · P_ref · F_f · F_H · F_C · F_relax |
| Heat capacity (effective) | C_total = m_fluid c_p,fluid + m_particle c_p,particle |
| Heat loss | P_loss = h_loss (T − T_env) |
| Energy balance | C_total dT/dt = P_mag − P_loss |
| Integration | Euler: T_{i+1} = T_i + (dT/dt)_i Δt; RK4 optional |
| Temperature rise | ΔT(t) = T(t) − T_initial |
| Local heating rate | HR_i = (T_i − T_{i−1}) / (t_i − t_{i−1}) [°C/s]; ×60 → °C/min |
| Calibration (Experimental-Calibrated) | T_cal = T_initial + α_fit (T_model − T_initial); α_fit = Σ ΔT_model ΔT_exp / Σ ΔT_model² |
| Goodness of fit | RMSE = √(Σ e²/N); MAE = Σ|e|/N; R² = 1 − SS_res/SS_tot |
| Estimated SAR (model) | SAR_est = P_mag(t=0) / m_particle [W/kg] — estimate, not a measurement |
| Estimated SAR (experimental initial slope) | SAR_est = C_total · (dT/dt)_initial / m_particle — uses assumed C_total, no heat-loss correction |
Important Scientific Limitations
This simulator provides model-based estimates. The calculated temperature, SAR, relaxation behavior, and heating rate depend strongly on assumptions regarding particle size, magnetic anisotropy, magnetic properties, thermal properties, suspension behavior, and experimental conditions. The model should be calibrated and validated against experimental measurements before scientific conclusions are drawn.
- Linear response theory is only quantitatively valid for Langevin parameter ξ = μ0 Ms V H/(kB T) < ~1.
- Hysteresis losses of large/ferromagnetic particles are not modelled.
- SAR values are labelled "Estimated SAR" and are not measured SAR values.
- Experimental-Calibrated mode scales the predicted temperature rise; it does not identify individual physical parameters.
- Results outside the validity range (e.g. above the boiling point) are not physically meaningful.