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  Temperature Compensation for Liquid Flowmeter
  ±Û¾´ÀÌ : ÀåÇö¼ö   °íÀ¯ID : jddast     ³¯Â¥ : 16-03-29 16:57     Á¶È¸ : 5798    
   Compensation.xlsx (49.5K), Down : 24, 2016-03-29 16:57:15
Liquid Flowmeter(ÀÚü compensation ¾ÈµÇ´Â typeÀÎ °æ¿ì)¿¡¼­ ³ª¿Â Volumetric flow°ª¿¡ Temperature¸¦ º¸»óÇÏ¿© Actual mass flow°è»êÀ» DCS¿¡ ½ÉÀ¸·Á°í ÇÕ´Ï´Ù.
¾Æ·¡¿Í °°ÀÌ ½ÄÀ» »ç¿ëÇ϶ó°í »ç¾÷ÁַκÎÅÍ ¹Þ¾ÒÀ¸³ª ¾î¶»°Ô Àû¿ëÇÏ´Â °ÍÀÎÁö ÀÇ°ßÀ» ¿©Âã°íÀÚ ÇÕ´Ï´Ù.
(Definition)
M_act : Compensated Mass flowrate
Q_read : Volumetric flowrate from flowmeter
Density_ref : Density of fluid assumed in meter design
Density_base : Density of flowing fluid at some known base temperature
T_act : Actual Temperature
T_base : Temperature at which density of flowing fluid is kown
J_act : Thermal expansion coefficient

Á¦ ³ª¸§´ë·Î ÷ºÎ¿¢¼¿°ú °°ÀÌ ¿Âµµ¿¡ °üÇÑ ¹Ðµµ data¸¦ °¡Áö°í ÷ºÎ½ÄÀ» Àû¿ëÇØ º¸¾Ò½À´Ï´Ù.
- Reference : flowmeter design °ª (220C)
- Base°ªÀº 0C
100m3/h »óŶó°í °¡Á¤ÇÏ°í, J_act°ªÀ» try&error·Î °è»êµÈ M_act°ú ÀÌ¹Ì ¾Ë°íÀÖ´Â actual mass°ªÀÌ µÇµµ·Ï ¿ªÀ¸·Î ÃßÁ¤Çϸé J_act °ªÀ» ±¸ÇÒ ¼ö°¡ ÀÖ½À´Ï´Ù. ÀÌ J_act°ªÀ» ´ëÀÔÇÏ¿© ´Ù¸¥ ¿Âµµ¿¡¼­ °è»êÀ» Çϸé Accuracy°¡ »ó´çÈ÷ ¶³¾îÁ³½À´Ï´Ù (¾à 10C¸¶´Ù 0.55%).
Á¦°¡ ½ÄÀ» À߸ø ÀÌÇØÇÑ °ÍÀÎÁö Ȥ½Ã ¾Æ½Ã´Â ºÐÀÌ °è½Ã¸é ¼³¸í/ÀÚ·á ºÎŹ µå¸®°Ú½À´Ï´Ù.

½ºÅ×Æijë Stefano   16-03-30 14:19
(1) ¾×»ó¹°ÁúÀÇ ¿Âµµº¸Á¤Àº ÃøÁ¤¿Âµµ(T_read)¿¡¼­ÀÇ ºÎÇÇÀ¯·® ÃøÁ¤°ª(Q_read)À¸·ÎºÎÅÍ ÃøÁ¤¿Âµµ¿¡¼­ÀÇ ¹Ðµµ(¥ñ_read)¸¦ Àû¿ëÇÏ¿© ½ÇÁ¦ÀÇ Áú·®À¯·®(M_act)À¸·Î ȯ»êÇÏ´Â ¹æ¹ýÀε¥ °èÃø±âÀÇ ÃøÁ¤°ª¿¡ ÀÌ¹Ì °è±âÀÇ ¼³°èÁ¶°Ç¿¡¼­ÀÇ ¹Ðµµ(¥ñ_ref)¿Í ±âÁؿµ¥¿¡¼­ÀÇ ¹Ðµµ(¥ñ_bas)´Â Æ÷ÇÔµÇ¾î ³ªÅ¸³ª°í ÀÖ´Ù°í º¸±â ¶§¹®¿¡ µ¿ÀÏÇÑ 100 m3/h¶ó°í Çصµ Áö½ÃÄ¡¿¡ ÀÌ¹Ì ±âº» ȯ»ê°è¼ö´Â Æ÷ÇԵǾî ÀÖÀ» °ÍÀ¸·Î °£Áֵ˴ϴÙ.  (°ú¿¬ ±×·±Áö À¯·®°èÃø ÃøÁ¤¿ø¸®¸¦ È®ÀÎÇØ º¸¼¼¿ä.)

µû¶ó¼­, ÀοëÇÑ ¼ö½ÄÀ» Àû¿ëÇÏ´Â °èÃø±â Çü½ÄÀº ¹Ì¸® Á¤ÇØÁ³°í ±× ¼ö½ÄºÎºÐ¸¸À» »ç¿ëÇؼ­ º¸Á¤Çϸé ÇØ´ç °èÃø±â¿¡¼­ ¿Âµµ¿¡ µû¸¥ ¹Ðµµº¸Á¤ÀÌ ¿Ï·áµÈ Áú·®À¯·®(M_act)À» ±¸ÇÏ¸é µÈ´Ù°í º¾´Ï´Ù.       

(2) ÁÖ¾îÁø ¼ö½ÄÀ» º¯ÇüÇϸé

M_act = Q_act * ¥ñ_act =  Q_read * ¥ñ_read = Q_ref * ¥ñ_ref = Q_base * ¥ñ_base
=Q_read * [ (¥ñ_ref)*(¥ñ_base)/{1+j_act*(T_act-T_base)}]^0.5  .........(1)   

ÇÑÆí,  v_base*{1+j_act*(T_act-T_base)} = (v_act)  .......................(2)  ºñ¿ëÀû v_base=1/¥ñ_base, v_act=1/¥ñ_act 

{1+j_act*(T_act-T_base)} = (v_act)/(v_base) = (1/¥ñ_act)/(1/¥ñ_base) = (¥ñ_base)/(¥ñ_act) ...(3) À̸¦ (1)¿¡ ´ëÀÔÈÄ Á¤¸®

M_act = Q_read * ¥ñ_read
= Q_read * [ (¥ñ_ref)*(¥ñ_base)/{1+j_act*(T_act-T_base)}]^0.5
= Q_read * [ (¥ñ_ref)*(¥ñ_base)/{(¥ñ_base)/(¥ñ_act) }]^0.5
= Q_read * [ (¥ñ_ref)*(¥ñ_act) ]^0.5 ............................................(4)
= Q_read * {(¥ñ_ref/(¥ñ_act)}^0.5 * [ (¥ñ_act)*(¥ñ_act) ]^0.5
= [ Q_read * {(¥ñ_ref/(¥ñ_act)}^0.5 ] *  (¥ñ_act)   
= Q_act * ¥ñ_act ..............................................................(1),(5)

µû¶ó¼­ Q_act =  Q_read * {(¥ñ_ref/(¥ñ_act)}^0.5  ..........................(6) 

´Ù¸¥ ¿Âµµ¿¡¼­ÀÇ ÃøÁ¤°ªµé·Î À¯»çÇÑ ¼ö½ÄÀ¸·Î ³ªÅ¸³¾ ¼ö ÀÖÀ½´Ï´Ù.  ÀÌÀÇ ³»¿ëÀ» »ìÆ캸¸é... °¢ ¿Âµµ¿¡¼­ÀÇ ÃøÁ¤°ªµéÀ» ¹ÐµµºñÀÇ -1/2½ÂÀÇ ºñ·Î ÃøÁ¤µÈ´Ù°í º¼ ¼ö ÀÖ½À´Ï´Ù.  (°á·ÐÀûÀ¸·Î ¾Õ¼­ ¼³¸íÇß´ø´ë·Î ´ç¿¬ÇÑ À̾߱⿴Áö¸¸, ÃøÁ¤°ªµéÀº ±âÁعеµ°ªÀÌ ´Þ¶óÁö¸é ´Þ¸® ÃøÁ¤µÈ´Ù°í º¼ ¼ö ÀÖ½À´Ï´Ù. )

(3) ¹®Á¦´Â j_act¸¦ ¾î´À Á¤µµ ±¸°£¿¡¼­ÀÇ ÆØâÀ²À» Àû¿ëÇϴ°¡¿¡ ´Þ·Á Àִµ¥  Full Range¿¡ ´ëÇØ Æò±ÕÆØâÀ²À» Àû¿ëÇÏ¸é ¿ÀÂ÷°¡ Ä¿Áö±â ¶§¹®¿¡  T_act, T_read, T_base, T_ref ¿Âµµ¸¦ Æ÷ÇÔÇ쵂 °èÀý¿¡ °ü°è¾øÀÌ ÃøÁ¤¹üÀ§¿¡ µé¾î¿À´Â ±¸°£¸¸À» Á¤ÇÏ¿© Æò±Õ ºÎÇÇ ÆØâÀ²À» Àû¿ëÇÏ¸é µÉ °ÍÀÔ´Ï´Ù.  µû¶ó¼­

T_a~ T_b (T_a<T_b) ±¸°£¿¡¼­ÀÇ ºÎÇÇÆØâÀ²,  j_a~b=  { (1/¥ñ_b - 1/¥ñ_a) / (1/¥ñ_a) }/(T_b-T_a) .....(7)  "ºÎÈ£¿¡ ÁÖÀÇ"

¿Âµµ¿µ¿ªÀ» ´õ ³ÐÈ÷¸é Àü±¸°£¿¡¼­ ÃøÁ¤ÇÒ ¼öµµ ÀÖ°ÚÁö¸¸ »ó½Ã ¿îÀüµÇ´Â ±¸°£À¸·Î Á¼Çô¼­ ¹Ðµµµ¥ÀÌÅͷκÎÅÍ º¸Á¤½ÄÀÇ Parameter (¿©±â¼­´Â j_a~b)¸¦ Àû¿ëÇϴ°ÍÀÌ ÃøÁ¤¿ÀÂ÷¸¦ ÁÙÀÌ´Â ÀÏÀÌ µÉ °ÍÀÔ´Ï´Ù. 

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