turbine_h_s

demo_using_lib/Turbine_H-S.py

@@ -3,20 +3,23 @@
 
  H-S(Mollier) Diagram of Steam Turbine Expansion
 
- 4 lines:
+ 6 lines:
     1.  Isobar line:p inlet
     2.  Isobar line:p outlet
     3.  isentropic line:  (p inlet ,t inlet h inlet,s inlet), (p outlet,s inlet)
     4.  Expansion line: inlet,outlet
+    5.  Isobar lines
+    6.  Isotherm lines   
 
 Author:   Cheng Maohua
 Email:    cmh@seu.edu.cn
 """
-from seuif97 import ph2t, ps2h, pt2h, pt2s
+from seuif97 import ph2t, ps2h, pt2h, pt2s, ts2h, ps2t
 
 import matplotlib.pyplot as plt
 import numpy as np
 
+
 def turbine_stage(pi, ti, pe, te):
     """ superheated steam zone """
     hi = pt2h(pi, ti)
@@ -28,6 +31,7 @@ def turbine_stage(pi, ti, pe, te):
     real_hd = (hi - he)
     return hi, si, he, se, ishd, (100.0 * real_hd / ishd)
 
+
 class Turbine:
 
     def __init__(self, pin, tin, pex, tex):
@@ -62,39 +66,68 @@ def expansionline(self):
         s_expL = np.array([self.sin, self.sex])
 
         # plot lines
-        plt.figure(figsize=(6, 8))
+        plt.figure(figsize=(6, 9))
         plt.title("H-S(Mollier) Diagram of Steam Turbine Expansion")
+
         plt.plot(s_isopin, h_isopin, 'b-')  # Isobar line: pin
         plt.plot(s_isopex, h_isopex, 'b-')  # Isobar line: pex
 
         plt.plot(s_isos, h_isos, 'ys-')  # isoentropic line:
         plt.plot(s_expL, h_expL, 'r-', label='Expansion Line')
         plt.plot(s_expL, h_expL, 'rs')
 
+        # Isobar lines and Isotherm lines
+        s_diff = self.sex-self.sin+2 * sdelta
+        isos = np.array([self.sin-sdelta + s_diff*(i/7) for i in range(8)])
+        # Isobar lines to plot,MPa
+        p_diff = self.pin-self.pex
+        isop = np.array([self.pex+p_diff*(i/7) for i in range(8)])
+        for p in isop:
+            h = np.array([ps2h(p, s) for s in isos])
+            plt.plot(isos, h, 'b--', lw=0.5)
+            # annotate Isobar line
+            txt = "%.2f MPa" % (p)
+            plt.annotate(txt,
+                         xy=(isos[6], h[6]), xycoords='data',
+                         xytext=(+1, -10), textcoords='offset points', fontsize=6)
+
+        # Isotherm lines to plot, ºC
+        t_isos = ps2t(self.pex, self.sin)
+        t_diff = self.tin - t_isos
+        isot = np.array([t_isos+t_diff*(i/9) for i in range(10)])
+        for t in isot:
+            h = np.array([ts2h(t, s) for s in isos])
+            plt.plot(isos, h, 'm', lw=0.5)
+            # annotate Isotherm line
+            txt = "%.2f°C" % (t)
+            plt.annotate(txt,
+                         xy=(isos[0], h[0]), xycoords='data',
+                         xytext=(+1, -10), textcoords='offset points', fontsize=6)
+
         _title = 'The isentropic efficiency = ' + \
             r'$\frac{h_1-h_2}{h_1-h_{2s}}$' + '=' + \
             '{:.2f}'.format(self.ef) + '%'
 
         plt.legend(loc="center", bbox_to_anchor=[
-                   0.6, 0.9], ncol=2, shadow=True, title=_title)
+                   0.6, 0.94], ncol=2, shadow=True, title=_title)
 
         # annotate the inlet and exlet
-        txt = "h1(%.2f,%.2f)" % (self.pin, self.tin)
+        txt = "%.2fMPa,%.2f°C" % (self.pin, self.tin)
         plt.annotate(txt,
                      xy=(self.sin, self.hin), xycoords='data',
-                     xytext=(+1, +10), textcoords='offset points', fontsize=10,
+                     xytext=(+1, +10), textcoords='offset points', fontsize=8,
                      arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2"))
 
-        txt = "h2(%.2f,%.2f)" % (self.pex, self.tex)
+        txt = "%.2fMPa,%.2f°C" % (self.pex, self.tex)
         plt.annotate(txt,
                      xy=(self.sex, self.hex), xycoords='data',
-                     xytext=(+1, +10), textcoords='offset points', fontsize=10,
+                     xytext=(+1, +10), textcoords='offset points', fontsize=8,
                      arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2"))
        # annotate h2s
-        txt = "h2s(%.2f,%.2f)" % (self.pex, ph2t(self.pex, h_isos[1]))
+        txt = "%.2fMPa,%.2f°C" % (self.pex, ph2t(self.pex, h_isos[1]))
         plt.annotate(txt,
                      xy=(self.sin, h_isos[1]), xycoords='data',
-                     xytext=(+1, +10), textcoords='offset points', fontsize=10,
+                     xytext=(+1, +10), textcoords='offset points', fontsize=8,
                      arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2"))
 
         plt.xlabel('s(kJ/(kg.K))')