seuif97 2.3.3

The high-speed IAPWS-IF97 package in Rust with Python bindings

SEUIF97

The version of seuif97 2 is the Python API of the high-speed IAPWS-IF97 package in Rust. It is suitable for computation-intensive calculations, such as heat cycle calculations, simulations of non-stationary processes, real-time process monitoring and optimizations.

Through the high-speed package, the results of the IAPWS-IF97 are accurately produced at about 5-20x speed-up compared to using the powi() of the Rust standard library in the for loop directly when computing the basic equations of Regions 1, 2, and 3.

Acceleration Methods

• Loop Tiling Method: Unleashes the full power of compiler optimizations, surpassing the performance of the single loop.

• Recurrence Method for Multi-Polynomial Evaluation: By leveraging the relationship between polynomials and their derivatives, only a single polynomial needs to be computed directly. The remaining values are derived via multiplication or division by the base. This approach eliminates redundant calculations and significantly improves performance.

Input Pairs and Properties

In the package, 36 thermodynamic, transport and further properties can be calculated.

The following 12 input pairs are implemented:

  (p,t) (p,h) (p,s) (p,v) 
  
  (p,x) (t,x) (h,x) (s,x) 

  (t,h) (t,s) (t,v) 

  (h,s)

Functions

The two types of functions are provided in the package.

1. the input property pairs and the property ID(o_id) to get the value of the specified property

2. the input property pairs to get one of p,t,h,s,v or x directly

The input property pairs and the property ID

  ??(in1,in2,o_id)

• the first, second input parameters: the input property pairs
• the third input parameters: the property ID of the calculated property - o_id
• the return: the calculated property value of o_id

pt(p,t,o_id)
ph(p,h,o_id)
ps(p,s,o_id)
pv(p,v,o_id)

th(t,h,o_id)
ts(t,s,o_id)
tv(t,v,o_id)

hs(h,s,o_id)

px(p,x,o_id)
tx(p,x,o_id)
hx(h,x,o_id)
sx(s,x,o_id)

The input property pairs

  ??2?(in1,in2)

• the ? in 2? is the one of p,t,h,s,v or x

pt2h(p, t)  pt2s(p, t)  pt2v(p, t)  pt2x(p, t)
ph2t(p, h)  ph2s(p, h)  ph2v(p, h)  ph2x(p, h)   
ps2t(p, s)  ps2h(p, s)  ps2v(p, s)  ps2x(p, s)  
pv2t(p, v)  pv2h(p, v)  pv2s(p, v)  pv2x(p, v)  

hs2p(h, s)  hs2t(h, s)  hs2v(h, s)  hs2x(h, s)    

th2p(t, h)  th2s(t, h)  th2v(t, h)  th2x(t, h)   
ts2p(t, s)  ts2h(t, s)  ts2v(t, s)  ts2x(t, s)  
tv2p(t, v)  tv2h(t, v)  tv2s(t, v)  tv2x(t, v)  

px2t(p, x)  px2h(p, x)  px2s(p, x)  px2v(p, x)
tx2p(t, x)  tx2h(t, x)  tx2s(t, x)  tx2v(t, x)

hx2p(h, x)  hx2t(h, x)  hx2s(h, x)  hx2v(h, x)
sx2p(s, x)  sx2t(s, x)  sx2h(s, x)  sx2v(s, x)

Example

from seuif97 import *

OH=4

p=16.0
t=535.1
# ??(in1,in2,o_id)
h=pt(p,t,OH)
# ??2?(in1,in2)
s=pt2s(p,t)
print(f"p={p}, t={t} h={h:.3f} s={s:.3f}")

Examples

• T-S Diagram

• H-S Diagram

• H-S Diagram of Steam Turbine Expansion

• The Hybrid Steady-state Simulator of Rankine Cycle in Python

Properties

Property	Unit	Symbol	o_id	o_id(i32)
Pressure	MPa	p	OP	0
Temperature	°C	t	OT	1
Density	kg/m³	ρ	OD	2
Specific Volume	m³/kg	v	OV	3
Specific enthalpy	kJ/kg	h	OH	4
Specific entropy	kJ/(kg·K)	s	OS	5
Specific exergy	kJ/kg	e	OE	6
Specific internal energy	kJ/kg	u	OU	7
Specific isobaric heat capacity	kJ/(kg·K)	cp	OCP	8
Specific isochoric heat capacity	kJ/(kg·K)	cv	OCV	9
Speed of sound	m/s	w	OW	10
Isentropic exponent		k	OKS	11
Specific Helmholtz free energy	kJ/kg	f	OF	12
Specific Gibbs free energy	kJ/kg	g	OG	13
Compressibility factor		z	OZ	14
Steam quality		x	OX	15
Region		r	OR	16
Isobaric cubic expansion coefficient	1/K	ɑv	OEC	17
Isothermal compressibility	1/MPa	kT	OKT	18
Partial derivative (∂V/∂T)p	m³/(kg·K)	(∂V/∂T)p	ODVDT	19
Partial derivative (∂V/∂p)T	m³/(kg·MPa)	(∂v/∂p)T	ODVDP	20
Partial derivative (∂P/∂T)v	MPa/K	(∂p/∂T)v	ODPDT	21
Isothermal throttling coefficient	kJ/(kg·MPa)	δt	OIJTC	22
Joule-Thomson coefficient	K/MPa	μ	OJTC	23
Dynamic viscosity	Pa·s	η	ODV	24
Kinematic viscosity	m²/s	ν	OKV	25
Thermal conductivity	W/(m.K)	λ	OTC	26
Thermal diffusivity	m²/s	a	OTD	27
Prandtl number		Pr	OPR	28
Surface tension	N/m	σ	OST	29
Static Dielectric Constant		ε	OSDC	30
Isochoric pressure coefficient	1/K	β	OPC	31
Isothermal stress coefficient	kg/m³	βp	OBETAP	32
Fugacity coefficient		fi	OFI	33
Fugacity	MPa	f*	OFU	34
Relative pressure coefficient	1/K	αp	OAFLAP	35