Create thermal_model.py

thermal_model.py

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+"""
+Thermal Cooling Performance Model for Jacket-and-Denim Ensemble
+================================================================
+
+This module implements a holistic thermal analysis model for evaluating
+the passive cooling performance of a leather jacket and denim jeans combination.
+Based on the IEEE paper "Thermal Overload: A Holistic Analysis of the 
+Jacket-and-Denim Heatsink Paradigm".
+
+The model treats the human body as a parallel thermal network with:
+- Upper body (jacket system): 3-zone parallel model
+- Lower body (pants system): single-zone model
+
+Author: Thermal Engineering Research Team
+License: MIT
+"""
+
+import math
+from typing import Dict, Tuple
+from dataclasses import dataclass
+
+
+@dataclass
+class ThermalResults:
+    """Data class to store thermal analysis results."""
+    # Upper body results
+    R_upper_equivalent: float
+    heat_dissipation_upper: float
+    
+    # Lower body results  
+    R_lower_total: float
+    heat_dissipation_lower: float
+    
+    # Total system results
+    total_heat_dissipation: float
+    total_effective_resistance: float
+    thermal_efficiency: float
+    performance_status: str
+
+
+class ThermalModel:
+    """
+    Thermal analysis model for jacket-and-denim ensemble.
+    
+    This class implements a full-body thermal resistance network model
+    to evaluate the passive cooling performance of the iconic outfit.
+    """
+    
+    def __init__(self):
+        """Initialize the thermal model with default parameters."""
+        # Default material properties (W/m·K)
+        self.k_leather = 0.15
+        self.k_cotton = 0.05
+        self.k_denim = 0.06
+        self.k_air = 0.026
+        
+        # Default material thicknesses (m)
+        self.d_leather = 0.0015
+        self.d_cotton = 0.001
+        self.d_denim = 0.0015
+        
+        # Default convection coefficients (W/m²·K)
+        self.h_open = 15.0     # Open front zone (chimney effect)
+        self.h_loose = 6.0     # Loose fit zone
+        self.h_tight = 3.5     # Tight fit zone
+        self.h_lower = 5.0     # Lower body average
+    
+    def calculate_cooling_performance(
+        self,
+        # Environmental & physiological parameters
+        T_skin: float = 33.5,           # Skin temperature (°C)
+        T_ambient: float = 26.0,        # Ambient temperature (°C)
+        A_total: float = 1.8,           # Total surface area (m²)
+        
+        # Body region distribution
+        A_frac_upper: float = 0.6,      # Upper body area fraction
+        
+        # Material thermal conductivities (W/m·K)
+        k_leather: float = None,
+        k_cotton: float = None,
+        k_denim: float = None,
+        k_air: float = None,
+        
+        # Material thicknesses (m)
+        d_leather: float = None,
+        d_cotton: float = None,
+        d_denim: float = None,
+        d_air_gap_upper: float = 0.01,  # Upper body air gap
+        d_air_gap_lower: float = 0.005, # Lower body air gap
+        
+        # Upper body geometry & convection parameters
+        f_open: float = 0.35,           # Open front fraction
+        f_loose: float = 0.50,          # Loose fit fraction
+        h_open: float = None,
+        h_loose: float = None,
+        h_tight: float = None,
+        
+        # Lower body convection parameter
+        h_lower: float = None
+    ) -> ThermalResults:
+        """
+        Calculate the passive cooling performance of the full ensemble.
+        
+        The model divides the body into two parallel thermal networks:
+        1. Upper body (Jacket System): 3-zone parallel model
+        2. Lower body (Pants System): single-zone model
+        
+        Returns:
+            ThermalResults: Complete thermal analysis results
+        """
+        
+        # Use instance defaults if parameters not provided
+        k_leather = k_leather or self.k_leather
+        k_cotton = k_cotton or self.k_cotton
+        k_denim = k_denim or self.k_denim
+        k_air = k_air or self.k_air
+        
+        d_leather = d_leather or self.d_leather
+        d_cotton = d_cotton or self.d_cotton
+        d_denim = d_denim or self.d_denim
+        
+        h_open = h_open or self.h_open
+        h_loose = h_loose or self.h_loose
+        h_tight = h_tight or self.h_tight
+        h_lower = h_lower or self.h_lower
+        
+        # Validate inputs
+        if f_open + f_loose > 1.0:
+            raise ValueError("Upper body area fractions (f_open + f_loose) cannot exceed 1.0")
+        
+        if T_skin <= T_ambient:
+            raise ValueError("Skin temperature must be higher than ambient temperature")
+        
+        # --- Area Distribution ---
+        A_upper = A_total * A_frac_upper
+        A_lower = A_total * (1 - A_frac_upper)
+        
+        # --- Calculate Base Thermal Resistances (m²·K/W) ---
+        R_cond_leather = d_leather / k_leather
+        R_cond_cotton = d_cotton / k_cotton
+        R_cond_denim = d_denim / k_denim
+        R_cond_air_upper = d_air_gap_upper / k_air
+        R_cond_air_lower = d_air_gap_lower / k_air
+        
+        R_conv_open = 1 / h_open
+        R_conv_loose = 1 / h_loose
+        R_conv_tight = 1 / h_tight
+        R_conv_lower = 1 / h_lower
+        
+        # --- Upper Body Heat Transfer Analysis ---
+        # Calculate series resistance for each zone
+        R_zone_open = R_cond_cotton + R_conv_open
+        R_zone_loose = R_cond_cotton + R_cond_air_upper + R_cond_leather + R_conv_loose
+        R_zone_tight = R_cond_cotton + R_cond_leather + R_conv_tight
+        
+        # Calculate equivalent resistance for upper body parallel network
+        f_tight = 1 - f_open - f_loose
+        inv_R_upper = (f_open / R_zone_open) + (f_loose / R_zone_loose) + (f_tight / R_zone_tight)
+        R_upper_equiv = 1 / inv_R_upper
+        
+        # Calculate upper body heat dissipation
+        delta_T = T_skin - T_ambient
+        Q_upper = (A_upper * delta_T) / R_upper_equiv
+        
+        # --- Lower Body Heat Transfer Analysis ---
+        # Calculate series resistance for lower body
+        R_lower_total = R_cond_denim + R_cond_air_lower + R_conv_lower
+        
+        # Calculate lower body heat dissipation
+        Q_lower = (A_lower * delta_T) / R_lower_total
+        
+        # --- Total System Performance ---
+        Q_total = Q_upper + Q_lower
+        R_total_effective = (A_total * delta_T) / Q_total
+        
+        # Calculate thermal efficiency (compared to 100W TDP)
+        TDP_reference = 100.0
+        thermal_efficiency = (Q_total / TDP_reference) * 100
+        
+        # Determine performance status
+        if Q_total >= TDP_reference:
+            performance_status = "PASS - Adequate cooling performance"
+        elif Q_total >= 0.9 * TDP_reference:
+            performance_status = "MARGINAL - Near thermal limit"
+        else:
+            performance_status = f"FAIL - {TDP_reference - Q_total:.1f}W thermal deficit"
+        
+        return ThermalResults(
+            R_upper_equivalent=R_upper_equiv,
+            heat_dissipation_upper=Q_upper,
+            R_lower_total=R_lower_total,
+            heat_dissipation_lower=Q_lower,
+            total_heat_dissipation=Q_total,
+            total_effective_resistance=R_total_effective,
+            thermal_efficiency=thermal_efficiency,
+            performance_status=performance_status
+        )
+    
+    def get_performance_summary(self, results: ThermalResults, TDP: float = 100.0) -> Dict[str, str]:
+        """
+        Generate a human-readable performance summary.
+        
+        Args:
+            results: ThermalResults object from calculate_cooling_performance
+            TDP: Target thermal design power in watts
+            
+        Returns:
+            Dictionary containing formatted summary strings
+        """
+        summary = {
+            "Upper Body Performance": f"{results.heat_dissipation_upper:.1f}W "
+                                    f"(R_eq = {results.R_upper_equivalent:.3f} m²·K/W)",
+            
+            "Lower Body Performance": f"{results.heat_dissipation_lower:.1f}W "
+                                    f"(R_total = {results.R_lower_total:.3f} m²·K/W)",
+            
+            "Total Heat Dissipation": f"{results.total_heat_dissipation:.1f}W",
+            
+            "Thermal Efficiency": f"{results.thermal_efficiency:.1f}% of {TDP}W target",
+            
+            "Performance Status": results.performance_status,
+            
+            "Engineering Assessment": self._get_engineering_assessment(results, TDP)
+        }
+        
+        return summary
+    
+    def _get_engineering_assessment(self, results: ThermalResults, TDP: float) -> str:
+        """Generate engineering assessment based on results."""
+        Q_total = results.total_heat_dissipation
+        
+        if Q_total >= TDP:
+            return ("System operates within thermal limits. "
+                   "Passive cooling is sufficient for sustained operation.")
+        elif Q_total >= 0.95 * TDP:
+            return ("System operates at thermal edge. "
+                   "Consider environmental optimization or brief duty cycles.")
+        elif Q_total >= 0.85 * TDP:
+            return ("Thermal deficit detected. "
+                   "Active cooling or garment optimization recommended.")
+        else:
+            return ("Significant thermal bottleneck. "
+                   "Major design modifications required for target TDP.")
+
+
+def demo_calculation():
+    """Demonstration of the thermal model with default parameters."""
+    model = ThermalModel()
+    results = model.calculate_cooling_performance()
+    summary = model.get_performance_summary(results)
+    
+    print("=" * 60)
+    print("THERMAL ANALYSIS: Jacket-and-Denim Heatsink Performance")
+    print("=" * 60)
+    
+    for key, value in summary.items():
+        print(f"{key:.<25}: {value}")
+    
+    print("\n" + "=" * 60)
+    print("Analysis complete. See full results above.")
+    
+    return results, summary
+
+
+if __name__ == "__main__":
+    demo_calculation()