White Flint, a $50 million shopping center on Rockville Pike, opened its doors yesterday to thousands of area consumers - who headed immediately for a 260,000-square-foot Bloomingdale's, the New York department store's largest retail facility outside Manhattan.

Only a handful of other stores were ready to open with Bloomies yesterday, which disappointed some of the shoppers. And the aisles at Lord & Taylor, a New York specialty store that gained an edge over Bloomingdale's by opening its third area store one week earlier, were virtually empty yesterday.

Lord & Taylor and Bloomies are engated at White Flint in their first head-to-head competition in a single mall and a Lord & Taylor spokeswoman said yesterday the initial week's sales "exceeded our expectations."

The shopping center has other features which were on public display for the first time yesterday, including a 20,000-square-foot, cafe-style dining facility that offers fast-food service from 12 different nationalities; an unusual three-level interior with glass-enclosed elevators and canvas banner paintings by Gay Glading; and the first of three planned "theme streets" of shops and boutiques.

One of the half-dozen stores opened yesterday was a branch of Ann Taylor , a medium to higher-priced apparel chain that features high-fashion, casual items. Store manager Jerri Stringer attributed her ability to begin business to the "efficiency" of Ann Taylor management, which delivered everything on time. The entire store had been set up in one day, she added.

Stringer forecast that White Flint, as a whole, would be unusually successful. "It's like a small community . . . a whole new world, the feeling is a lot like California . . . you don't feel cold, the mailman stopped by to introduce himself and the bank man stops in."

Formerly employed at the Ann Taylor store in Tysons Corner Center, Stringer said the new mall in Montgomery County is "warmer, a closely knit community." Both Tysons (which opened in 1968) and White Flint were built by Lerner Corp., a Wheaton-based shopping center developer.

As customers at Ann Taylor looked over what Stringer described as a combination of traditional and fantasy basic clothes, several of her 14 employees (many more than 200 persons applied for sales jobs) were handing out glasses of champagne.

But the center of attraction yesterday clearly was Bloomingdale's, where a live model walked barefoot through the lingerie department, wearing a sheer nightgown and handing out samples of Pucci perfume. Most people tried to act the sophisticate, not giving the model much notice. A few stared.

On another floor, men were sprayed with Aramis cologne as they walked down an aisle (by a Bloomingdale's salesman, who pointed the way to the Aramis sales counter). Samples of food produced with gourmet cooking products were popular on the bottom of four floors at Bloomies, and there was along line behind a sewing machine where monograms were being added free to towels in a special sale.

Elaine McDermott, who lives about two miles from the new mall, was one of those on line to get a towel monogrammed. "I really like it," she said of her first visit to a Bloomingdale's store. "I expect to see higher prices . . . I would rather come here than to the Hecht Co. or Woodies [Woodward & Lothrop] if the prices are comparable, the sales help are all very nice," she added.